Radiation imaging apparatus

International Nuclear Information System (INIS)

Lange, K.; Wiesen, E.J.; Woronowicz, E.M.

1981-01-01

Improvements in the uniformity and resolution of scintillation cameras are described in detail. One of the problems in scintillation cameras is the non-uniform response of the photomultiplier array to light signals which results in non-uniformity of the displayed image. A novel method of overcoming the problem is presented. By electronically processing the signals from the photomultiplier array it is possible to deduce four co-ordinate signals viz +x, -x, +y and -y; the signals are summed to give the energy of the scintillation event. Details of the electronic circuits required are given. (U.K.)

Performance of ultra-small silicon photomultiplier array with active area of 0.12 mm×0.12 mm

Energy Technology Data Exchange (ETDEWEB)

Yue, Wang; Zongde, Chen; Chenhui, Li; Ran, He; Shenyuan, Wang; Baicheng, Li; Ruiheng, Wang; Kun, Liang, E-mail: lk@bnu.edu.cn; Ru, Yang; Dejun, Han

2015-07-01

We report the performance of an ultra-small silicon photomultiplier (SiPM) line array with 7 elements of 0.12×0.12 mm{sup 2} in active area, 0.2 mm in pitch and 120 micro cells in one element. The device features an epitaxial bulk quenching resistor concept, demonstrated high geometrical fill factor of 41% and photon detection efficiency (PDE) of 25.4% in the wavelength region between 430 nm and 480 nm while retaining high micro cell density around 10 000 mm{sup −2} and ~3 ns FWHM of dark pulses width; it also demonstrated dark count rate of less than 28.7 kHz, optical crosstalk of the order of 2% to 4%, and excellent photon number discrimination. A 0.15 mm×1.6 mm×1.6 mm lutetium yttrium oxyorthosilicate (LYSO) crystal, corresponding to the width, length and height respectively, was successfully coupled to the 1×7 SiPM array for possible ultra-highly resolved positron emission tomography (PET) applications. This novel type of device has advantages particularly for small active area since the performances, such as PDE and response speed is one of the best among SiPMs with similarly high density of micro cells. It may pave a way for this type of SiPM as a promising pixel position sensitive device in imaging sensor applications. - Highlights: • The ultra-small SiPM line array with active area of 0.12 mm×0.12 mm was presented. • The ultra-small SiPM employs the bulk silicon structure as quenching resistor. • A considerable dynamic range and PDE over 25.4% @ 430 nm to 480 nm were characterized.

Gain monitoring of telescope array photomultiplier cameras for the first 4 years of operation

Energy Technology Data Exchange (ETDEWEB)

Shin, B.K., E-mail: bkshin@hanyang.ac.kr [Hanyang University, Seongdong-gu, Seoul (Korea, Republic of); Tokuno, H.; Tsunesada, Y. [Tokyo Institute of Technology, Meguro, Tokyo (Japan); Abu-Zayyad, T. [University of Utah, High Energy Astrophysics Institute, Salt Lake City, UT (United States); Aida, R. [University of Yamanashi, Interdisciplinary Graduate School of Medicine and Engineering, Kofu, Yamanashi (Japan); Allen, M.; Anderson, R. [University of Utah, High Energy Astrophysics Institute, Salt Lake City, UT (United States); Azuma, R. [Tokyo Institute of Technology, Meguro, Tokyo (Japan); Barcikowski, E.; Belz, J.W.; Bergman, D.R.; Blake, S.A.; Cady, R. [University of Utah, High Energy Astrophysics Institute, Salt Lake City, UT (United States); Cheon, B.G., E-mail: bgcheon@hanyang.ac.kr [Hanyang University, Seongdong-gu, Seoul (Korea, Republic of); Chiba, J. [Tokyo University of Science, Noda, Chiba (Japan); Chikawa, M. [Kinki University, Higashi Osaka, Osaka (Japan); Cho, E.J. [Hanyang University, Seongdong-gu, Seoul (Korea, Republic of); Cho, W.R. [Yonsei University, Seodaemun-gu, Seoul (Korea, Republic of); Fujii, H. [Institute of Particle and Nuclear Studies, KEK, Tsukuba, Ibaraki (Japan); Fujii, T. [Osaka City University, Osaka, Osaka (Japan); and others

2014-12-21

The stability of the gain of the photomultiplier (PMT) camera for the Fluorescence Detector (FD) of the Telescope Array experiment was monitored using an {sup 241}Am loaded scintillator pulsers (YAP) and a diffused xenon flasher (TXF) for a selected set of 35 PMT-readout channels. From the monitoring of YAP pulses over four years of FD operation, we found slow monotonic drifts of PMT gains at a rate of −1.7∼+1.7%/year. An average of the PMT gains over the 35 channels stayed nearly constant with a rate of change measured at −0.01±0.31(stat)±0.21(sys)%/year. No systematic decrease of the PMT gain caused by the night sky background was observed. Monitoring by the TXF also tracked the PMT gain drift of the YAP at 0.88±0.14(stat)%/year.

A prototype detector using the neutron image intensifier and multi-anode type photomultiplier tube for pulsed neutron imaging

International Nuclear Information System (INIS)

Ishikawa, Hirotaku; Sato, Hirotaka; Hara, Kaoru Y.; Kamiyama, Takashi

2016-01-01

We developed a neutron two-dimensional (2-D) detector for pulsed neutron imaging as a prototype detector, which was composed of a neutron image intensifier and a multi-anode type photomultiplier tube. A neutron transmission spectrum of α-Fe plate was measured by the prototype detector, and compared with the one measured by a typical neutron 2-D detector. The spectrum was in reasonable agreement with the one measured by the typical detector in the neutron wavelength region above 0.15 nm. In addition, a neutron transmission image of a cadmium indicator was obtained by the prototype detector. The usefulness of the prototype detector for pulsed neutron imaging was demonstrated. (author)

Performance evaluation of a sub-millimeter spatial resolution PET detector module using a digital silicon photomultiplier coupled LGSO array

Energy Technology Data Exchange (ETDEWEB)

Leem, Hyun Tae [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Choi, Yong, E-mail: ychoi@sogang.ac.kr [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Kim, Kyu Bom; Lee, Sangwon [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Yamamoto, Seiichi [Department of Medical Technology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Yeom, Jung-Yeol, E-mail: jungyeol@korea.ac.kr [School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of)

2017-02-21

In positron emission tomography (PET) for breast, brain and small animal imaging, the spatial resolution of a PET detector is crucial to obtain high quality PET images. In this study, a PET detector for sub-millimeter spatial resolution imaging purpose was assembled using 4×4 pixels of a digital silicon photomultiplier (dSiPM, DPC-3200-22-44, Philips) coupled with a 15×15 LGSO array with BaSO{sub 4} reflector, and a 1 mm thick acrylic light guide for light distribution between the dSiPM pixels. The active area of each dSiPM pixel was 3.2×3.9 mm{sup 2} and the size of each LGSO scintillator element was 0.7×0.7×6 mm{sup 3}. In this paper, we experimentally demonstrated the performance of the PET detector by measuring the energy resolution, 2D flood map, peak to valley (P/V) ratio, and coincidence resolving time (CRT). All measurements were performed at a temperature of 10±1 ℃. The average energy resolution was 15.6% (without correcting for saturation effects) at 511 keV and the best CRT was 242±5 ps. The 2D flood map obtained with an energy window of 400–600 keV demonstrated clear identification of all pixels, and the average P/V ratio of the X- and Y-directions were 7.31 and 7.81, respectively. This study demonstrated that the PET detector could be suitable for application in high resolution PET while achieving good timing resolution.

A photomultiplier-based secondary electron imaging system for a nuclear microprobe

International Nuclear Information System (INIS)

Alves, L.C.; Breese, M.B.H.; Silva, M.F. da; Soares, J.C.

2002-01-01

The ability to define, or recognise particular regions of interest or surface features is vital to the analysis and interpretation of spatially-resolved images collected with a nuclear microprobe. However, good topographic image contrast is difficult to accomplish using PIXE or RBS images due to their inherent insensitivity to topography, lack of elemental variation or poor statistics. Topographic image contrast is commonly obtained in scanning electron microscopy (SEM) by detecting a large flux of secondary electrons produced by the focused keV electron beam. Similar systems have not been widely used on nuclear microprobes due to ion beam intensity fluctuations, which limit the minimum resolvable contrast and present a major limitation for this technique. This paper describes a secondary electron imaging system which has been developed on the Lisbon microprobe. It is based on a scintillator, a photomultiplier operated in a pulsed mode, a pulse shaping electronic chain and ADC, and requires no changes to the existing data acquisition system. Examples of the images obtained from materials such as patterned SiGe wafers and hydrogen-implanted silicon are given, and compared with SEM or optical images

photomultiplier tubes

CERN Multimedia

photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

photomultiplier tube

CERN Multimedia

photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

Model independent approach to the single photoelectron calibration of photomultiplier tubes

Energy Technology Data Exchange (ETDEWEB)

Saldanha, R.; Grandi, L.; Guardincerri, Y.; Wester, T.

2017-08-01

The accurate calibration of photomultiplier tubes is critical in a wide variety of applications in which it is necessary to know the absolute number of detected photons or precisely determine the resolution of the signal. Conventional calibration methods rely on fitting the photomultiplier response to a low intensity light source with analytical approximations to the single photoelectron distribution, often leading to biased estimates due to the inability to accurately model the full distribution, especially at low charge values. In this paper we present a simple statistical method to extract the relevant single photoelectron calibration parameters without making any assumptions about the underlying single photoelectron distribution. We illustrate the use of this method through the calibration of a Hamamatsu R11410 photomultiplier tube and study the accuracy and precision of the method using Monte Carlo simulations. The method is found to have significantly reduced bias compared to conventional methods and works under a wide range of light intensities, making it suitable for simultaneously calibrating large arrays of photomultiplier tubes.

Position-sensitive gaseous photomultipliers research and applications

CERN Document Server

Francke, Tom; Peskov, Vladimir

2016-01-01

Gaseous photomultipliers are defined as gas-filled devices capable of recording single ultraviolet (UV) and visible photons with high position resolution. Used in a variety of research areas, these detectors can be paired with computers to treat and store imaging information of UV-light. Position-Sensitive Gaseous Photomultipliers: Research and Applications explores the advancement of gaseous detectors as applied for single photon detection. Emphasizing emerging perspectives and new ways to apply gaseous detectors across research fields, this research-based publication is an essential reference source for engineers, physicists, graduate-level students, and researchers.

A new detector concept for silicon photomultipliers

Energy Technology Data Exchange (ETDEWEB)

Sadigov, A., E-mail: saazik@yandex.ru [National Nuclear Research Center, Baku (Azerbaijan); Ahmadov, F.; Ahmadov, G. [National Nuclear Research Center, Baku (Azerbaijan); Ariffin, A.; Khorev, S. [Zecotek Photonics Inc., Vancouver (Canada); Sadygov, Z. [National Nuclear Research Center, Baku (Azerbaijan); Joint Institute for Nuclear Research, Dubna (Russian Federation); Suleymanov, S. [National Nuclear Research Center, Baku (Azerbaijan); Zerrouk, F. [Zecotek Photonics Inc., Vancouver (Canada); Madatov, R. [Institute of Radiation Problems, Baku (Azerbaijan)

2016-07-11

A new design and principle of operation of silicon photomultipliers are presented. The new design comprises a semiconductor substrate and an array of independent micro-phototransistors formed on the substrate. Each micro-phototransistor comprises a photosensitive base operating in Geiger mode and an individual micro-emitter covering a small part of the base layer, thereby creating, together with this latter, a micro-transistor. Both micro-emitters and photosensitive base layers are connected with two respective independent metal grids via their individual micro-resistors. The total value of signal gain in the proposed silicon photomultiplier is a result of both the avalanche gain in the base layer and the corresponding gain in the micro-transistor. The main goals of the new design are: significantly lower both optical crosstalk and after-pulse effects at high signal amplification, improve speed of single photoelectron pulse formation, and significantly reduce the device capacitance.

Characterization studies of Silicon Photomultipliers and crystals matrices for a novel time of flight PET detector

CERN Document Server

Auffray, Etiennette; Cortinovis, Daniele; Doroud, Katayoun; Garutti, Erika; Lecoq, Paul; Liu, Zheng; Martinez, Rosana; Paganoni, Marco; Pizzichemi, Marco; Silenzi, Alessandro; Xu, Chen; Zvolský, Milan

2015-01-01

This paper describes the characterization of crystal matrices and silicon photomultiplier arrays for a novel Positron Emission Tomography (PET) detector, namely the external plate of the EndoTOFPET-US system. The EndoTOFPET-US collaboration aims to integrate Time-Of-Flight PET with ultrasound endoscopy in a novel multimodal device, capable to support the development of new biomarkers for prostate and pancreatic tumors. The detector consists in two parts: a PET head mounted on an ultrasound probe and an external PET plate. The challenging goal of 1 mm spatial resolution for the PET image requires a detector with small crystal size, and therefore high channel density: 4096 LYSO crystals individually readout by Silicon Photomultipliers (SiPM) make up the external plate. The quality and properties of these components must be assessed before the assembly. The dark count rate, gain, breakdown voltage and correlated noise of the SiPMs are measured, while the LYSO crystals are evaluated in terms of light yield and en...

Optimization of Performance Parameters for Large Area Silicon Photomultipliers

Science.gov (United States)

Janzen, Kathryn

2008-10-01

The goal of the GlueX experiment is to search for exotic hybrid mesons as evidence of gluonic excitations in an effort to better understand confinement. A key component of the GlueX detector is the electromagnetic barrel calorimeter (BCAL) located immediately inside a superconducting solenoid of approximately 2.5T. Because of this arrangement, traditional vacuum photomultiplier tubes (PMTs) which are affected significantly by magnetic fields cannot be used on the BCAL. The use of Silicon photomultipliers (SiPMs) as front-end detectors has been proposed. While the largest SiPMs that have been previously employed by other experiments are 1x1 mm^2, GlueX proposes to use large area SiPMs each composed of 16 - 3x3 mm^2 cells in a 4x4 array. This puts the GlueX collaboration in the unique position of driving the technology for larger area sensors. In this talk I will discuss tests done in Regina regarding performance parameters of prototype SiPM arrays delivered by SensL, a photonics research and development company based in Ireland, as well as sample 1x1 mm^2 and 3x3 mm^2 SiPMs.

A superconducting supercollider calorimeter photomultiplier tube preamplifier circuit

Energy Technology Data Exchange (ETDEWEB)

Panescu, D; Lackey, J; Robl, P; Smith, W H [Wisconsin Univ., Madison, WI (United States). Physics Dept.

1992-07-15

This study presents the design of the front end amplifier for a scintillator calorimeter with photomultiplier tube (PMT) readout. The design is based on analytical computations and SPICE simulations, and is checked against tests performed on a prototyped circuit. We were looking to achieve (1) a very low droop within the 4 ns after the integration of the photomultiplier tube (PMT) signal was completed, (2) a very low noise figure for the whole amplifier in a 100 MHz bandwidth, (3) an input impedance optimized for the PMT which is actually used, (4) baseline restoration as quick as possible at the output of the clip amps, (5) no loss of information due to the saturation at intermediary stages (e.g. integrator), and (6) an output driving 100 {Omega} twisted pair cables, or 50 {Omega} coaxial cables, in order to transmit the signal to switched capacitor arrays for analog storage. (orig.).

The photomultiplier handbook

CERN Document Server

Wright, A G

2017-01-01

Photomultipliers are extremely sensitive light detectors that can detect single photons. In multiplying the charge produced by incident light by up to 100 million times, these devices are essential to a wide range of functions, from medical instrumentation to astronomical observations. This complete and authoritative guide will provide students, practitioners, and researchers with a deeper understanding of the operating principles of these devices. Authored by an experienced user and manufacturer of photomultipliers, this handbook gives the reader insights into photomultiplier behaviour as a means to optimize performance. Diffuse and low level light sources are best served with a photomultiplier for the detection of single photon emissions. Light detection and electron multiplication are statistical in nature and the mathematics of these processes is derived from first principles. The book covers other related topics such as scintillation counting, light guides, and large area detectors. The usually complicat...

Studies on a silicon-photomultiplier-based camera for Imaging Atmospheric Cherenkov Telescopes

Science.gov (United States)

Arcaro, C.; Corti, D.; De Angelis, A.; Doro, M.; Manea, C.; Mariotti, M.; Rando, R.; Reichardt, I.; Tescaro, D.

2017-12-01

Imaging Atmospheric Cherenkov Telescopes (IACTs) represent a class of instruments which are dedicated to the ground-based observation of cosmic VHE gamma ray emission based on the detection of the Cherenkov radiation produced in the interaction of gamma rays with the Earth atmosphere. One of the key elements of such instruments is a pixelized focal-plane camera consisting of photodetectors. To date, photomultiplier tubes (PMTs) have been the common choice given their high photon detection efficiency (PDE) and fast time response. Recently, silicon photomultipliers (SiPMs) are emerging as an alternative. This rapidly evolving technology has strong potential to become superior to that based on PMTs in terms of PDE, which would further improve the sensitivity of IACTs, and see a price reduction per square millimeter of detector area. We are working to develop a SiPM-based module for the focal-plane cameras of the MAGIC telescopes to probe this technology for IACTs with large focal plane cameras of an area of few square meters. We will describe the solutions we are exploring in order to balance a competitive performance with a minimal impact on the overall MAGIC camera design using ray tracing simulations. We further present a comparative study of the overall light throughput based on Monte Carlo simulations and considering the properties of the major hardware elements of an IACT.

Photomultiplier gain stabilisation

International Nuclear Information System (INIS)

Le Baud, P.; Sautiez, B.

1958-07-01

By the control and adjustment of magnetic deflection applied to the electron beam of a photomultiplier it has proved possible to flatten the gain curve, forming plateaux at levels dependent upon the voltage at intake. It should be possible to add this simple device to most photomultipliers on the market today. (author) [fr

Silicon Photomultipliers: Dark Current and its Statistical Spread

Directory of Open Access Journals (Sweden)

Roberto PAGANO

2012-03-01

Full Text Available Aim of this paper is to investigate on a statistical basis at the wafer level the relationship existing among the dark currents of the single pixel compared to the whole Silicon Photomultiplier array. This is the first time to our knowledge that such a comparison is made, crucial to pass this new technology to the semiconductor manufacturing standards. In particular, emission microscopy measurements and current measurements allowed us to conclude that optical trenches strongly improve the device performances.

Imaging spectroscopy using embedded diffractive optical arrays

Science.gov (United States)

Hinnrichs, Michele; Hinnrichs, Bradford

2017-09-01

Pacific Advanced Technology (PAT) has developed an infrared hyperspectral camera based on diffractive optic arrays. This approach to hyperspectral imaging has been demonstrated in all three infrared bands SWIR, MWIR and LWIR. The hyperspectral optical system has been integrated into the cold-shield of the sensor enabling the small size and weight of this infrared hyperspectral sensor. This new and innovative approach to an infrared hyperspectral imaging spectrometer uses micro-optics that are made up of an area array of diffractive optical elements where each element is tuned to image a different spectral region on a common focal plane array. The lenslet array is embedded in the cold-shield of the sensor and actuated with a miniature piezo-electric motor. This approach enables rapid infrared spectral imaging with multiple spectral images collected and processed simultaneously each frame of the camera. This paper will present our optical mechanical design approach which results in an infrared hyper-spectral imaging system that is small enough for a payload on a small satellite, mini-UAV, commercial quadcopter or man portable. Also, an application of how this spectral imaging technology can easily be used to quantify the mass and volume flow rates of hydrocarbon gases. The diffractive optical elements used in the lenslet array are blazed gratings where each lenslet is tuned for a different spectral bandpass. The lenslets are configured in an area array placed a few millimeters above the focal plane and embedded in the cold-shield to reduce the background signal normally associated with the optics. The detector array is divided into sub-images covered by each lenslet. We have developed various systems using a different number of lenslets in the area array. Depending on the size of the focal plane and the diameter of the lenslet array will determine the number of simultaneous different spectral images collected each frame of the camera. A 2 x 2 lenslet array will image

Modeling Photo-multiplier Gain and Regenerating Pulse Height Data for Application Development

Science.gov (United States)

Aspinall, Michael D.; Jones, Ashley R.

2018-01-01

Systems that adopt organic scintillation detector arrays often require a calibration process prior to the intended measurement campaign to correct for significant performance variances between detectors within the array. These differences exist because of low tolerances associated with photo-multiplier tube technology and environmental influences. Differences in detector response can be corrected for by adjusting the supplied photo-multiplier tube voltage to control its gain and the effect that this has on the pulse height spectra from a gamma-only calibration source with a defined photo-peak. Automated methods that analyze these spectra and adjust the photo-multiplier tube bias accordingly are emerging for hardware that integrate acquisition electronics and high voltage control. However, development of such algorithms require access to the hardware, multiple detectors and calibration source for prolonged periods, all with associated constraints and risks. In this work, we report on a software function and related models developed to rescale and regenerate pulse height data acquired from a single scintillation detector. Such a function could be used to generate significant and varied pulse height data that can be used to integration-test algorithms that are capable of automatically response matching multiple detectors using pulse height spectra analysis. Furthermore, a function of this sort removes the dependence on multiple detectors, digital analyzers and calibration source. Results show a good match between the real and regenerated pulse height data. The function has also been used successfully to develop auto-calibration algorithms.

photomultiplier tube

CERN Multimedia

A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

photomultiplier tube

CERN Multimedia

Philips. 150AVP. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

Stereo imaging and random array stratified imaging for cargo radiation inspecting

International Nuclear Information System (INIS)

Wang Jingjin; Zeng Yu

2003-01-01

This paper presents a Stereo Imaging and Random Array Stratified Imaging for cargo container radiation Inspecting. By using dual-line vertical detector array scan, a stereo image of inspected cargo can be obtained and watched with virtual reality view. The random detector array has only one-row of detectors but distributed in a certain horizontal dimension randomly. To scan a cargo container with this random array detector, a 'defocused' image is obtained. By using 'anti-random focusing', one layer of the image can be focused on the background of all defocused images from other layers. A stratified X-ray image of overlapped bike wheels is presented

Test and evaluation of IR detectors and arrays II; Proceedings of the Meeting, Orlando, FL, Apr. 22, 23, 1992

Science.gov (United States)

Hoke, Forney M.

The present conference discusses a radiometric calibration system for IR cameras, a methodology for testing IR focal-plane arrays in simulated nuclear radiation environments, process optimization for Si:As In-bumped focal-plane arrays, precise MTF measurements for focal-plane arrays, and IR focal-plane array crosstalk measurement. Also discussed are an imaging metric for IR focal-plane arrays, optical stimuli for high-volume automated testing of 2D HgCdTe focal-plane arrays, the evaluation of a solid-state photomultiplier focal-plane array for SDI, spectral effects on bulk photoconductors operated at cryogenic temperatures, and a novel technique for measuring the ionizing radiation effects in MOS transistors.

Performance evaluation of neuro-PET using silicon photomultipliers

Energy Technology Data Exchange (ETDEWEB)

Jung, Jiwoong; Choi, Yong, E-mail: ychoi@sogang.ac.kr; Jung, Jin Ho, E-mail: jinho1115@gmail.com; Kim, Sangsu; Im, Ki Chun

2016-05-21

Recently, we have developed the second prototype Silicon photomultiplier (SiPM) based positron emission tomography (PET) scanner for human brain imaging. The PET system was comprised of detector block which consisted of 4×4 SiPMs and 4×4 Lutetium Yttrium Orthosilicate arrays, charge signal transmission method, high density position decoder circuit and FPGA-embedded ADC boards. The purpose of this study was to evaluate the performance of the newly developed neuro-PET system. The energy resolution, timing resolution, spatial resolution, sensitivity, stability of the photo-peak position and count rate performance were measured. Tomographic image of 3D Hoffman brain phantom was also acquired to evaluate imaging capability of the neuro-PET. The average energy and timing resolutions measured for 511 keV gamma rays were 17±0.1% and 3±0.3 ns, respectively. Spatial resolution and sensitivity at the center of field of view (FOV) were 3.1 mm and 0.8%, respectively. The average scatter fraction was 0.4 with an energy window of 350–650 keV. The maximum true count rate and maximum NECR were measured as 43.3 kcps and 6.5 kcps at an activity concentration of 16.7 kBq/ml and 5.5 kBq/ml, respectively. Long-term stability results show that there was no significant change in the photo-peak position, energy resolution and count rate for 60 days. Phantom imaging studies were performed and they demonstrated the feasibility for high quality brain imaging. The performance tests and imaging results indicate that the newly developed PET is useful for brain imaging studies, if the axial FOV is extended to improve the system sensitivity.

Operation and first results of the NEXT-DEMO prototype using a silicon photomultiplier tracking array

International Nuclear Information System (INIS)

Álvarez, V; Cárcel, S; Cervera, A; Díaz, J; Ferrario, P; Gil, A; Borges, F I G; Conde, C A N; Dias, T H V T; Fernandes, L M P; Freitas, E D C; Castel, J; Cebrián, S; Dafni, T; Egorov, M; Gehman, V M; Goldschmidt, A; Esteve, R; Evtoukhovitch, P; Ferreira, A L

2013-01-01

NEXT-DEMO is a high-pressure xenon gas TPC which acts as a technological test-bed and demonstrator for the NEXT-100 neutrinoless double beta decay experiment. In its current configuration the apparatus fully implements the NEXT-100 design concept. This is an asymmetric TPC, with an energy plane made of photomultipliers and a tracking plane made of silicon photomultipliers (SiPM) coated with TPB. The detector in this new configuration has been used to reconstruct the characteristic signature of electrons in dense gas, demonstrating the ability to identify the MIP and ''blob'' regions. Moreover, the SiPM tracking plane allows for the definition of a large fiducial region in which an excellent energy resolution of 1.82% FWHM at 511 keV has been measured (a value which extrapolates to 0.83% at the xenon Q ββ )

Photomultiplier protector for a fluorometer

International Nuclear Information System (INIS)

Priarone, P.; St John, P.A.

1982-01-01

The photometer is adapted for sensing radiation emitted by a chemical sample held in a cuvette received in a first compartment and includes a highly sensitive photomultiplier in a second compartment adjacent the first compartment for detecting fluorescent radiation emitted by the chemical sample and passing through an opening between the compartments. A mechanical protector assembly is provided for protecting the photomultiplier from ambient light and includes a movable light shield movable between a first position blocking the opening and a second position not blocking the opening. A knob is provided for moving the light shield to the first position to protect the photomultiplier from light entering from the first compartment when the first compartment is opened for insertion or removal of a cuvette, and for moving the light shield to the second position not blocking the opening to permit radiation emitted by the chemical sample to impinge upon the photomultiplier in the second compartment. The photometer also includes a mechanical interlocking assembly for ensuring that the first compartment cannot be opened unless the light shield is in the first position to prevent ambient light from entering the second compartment from the first compartment and reaching the photomultiplier

Development of Silicon Photomultipliers and their Applications to GlueX Calorimetry

Energy Technology Data Exchange (ETDEWEB)

Smith, Elton S. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2016-07-01

The GlueX experiment is a photoproduction experiment in Hall D at Jefferson Lab that is being commissioned for use with the new 12 GeV accelerator. The purpose of the experiment is to search for Hybrid mesons, which are mesons with quark and gluon degrees of freedom. The barrel calorimeter of GlueX is instrumented with 4000 large-area (1.2 x1.2 cm2) silicon photomultipliers (SiPMs). These photon sensors have properties similar to vacuum photomultipliers, but are unaffected by high magnetic fields. In our experiment they operate in magnetic fields exceeding 1T. After extensive tests with a variety of sensors, we chose the S12045(X) custom SiPM arrays manufactured by Hamamatsu Corporation, also known as multi-pixel photon counters (MPPCs). We will give an overview of this new technology as well as the experience gained during two commissioning periods with beam.

Development of silicon photomultipliers and their applications to GlueX calorimetry

Energy Technology Data Exchange (ETDEWEB)

Smith, Elton S., E-mail: elton@jlab.org [Jefferson Lab, Newport News, VA 23606 (United States)

2016-07-07

The GlueX experiment is a photoproduction experiment in Hall D at Jefferson Lab that is being commissioned for use with the new 12 GeV accelerator. The purpose of the experiment is to search for Hybrid mesons, which are mesons with quark and gluon degrees of freedom. The barrel calorimeter of GlueX is instrumented with 4000 large-area (1.2 × 1.2 cm{sup 2}) silicon photomultipliers (SiPMs). These photon sensors have properties similar to vacuum photomultipliers, but are unaffected by high magnetic fields. In our experiment they operate in magnetic fields exceeding 1T. After extensive tests with a variety of sensors, we chose the S12045(X) custom SiPM arrays manufactured by Hamamatsu Corporation, also known as multi-pixel photon counters (MPPCs). We will give an overview of this new technology as well as the experience gained during two commissioning periods with beam.

Passive cavitation imaging with ultrasound arrays.

Science.gov (United States)

Salgaonkar, Vasant A; Datta, Saurabh; Holland, Christy K; Mast, T Douglas

2009-12-01

A method is presented for passive imaging of cavitational acoustic emissions using an ultrasound array, with potential application in real-time monitoring of ultrasound ablation. To create such images, microbubble emissions were passively sensed by an imaging array and dynamically focused at multiple depths. In this paper, an analytic expression for a passive image is obtained by solving the Rayleigh-Sommerfield integral, under the Fresnel approximation, and passive images were simulated. A 192-element array was used to create passive images, in real time, from 520-kHz ultrasound scattered by a 1-mm steel wire. Azimuthal positions of this target were accurately estimated from the passive images. Next, stable and inertial cavitation was passively imaged in saline solution sonicated at 520 kHz. Bubble clusters formed in the saline samples were consistently located on both passive images and B-scans. Passive images were also created using broadband emissions from bovine liver sonicated at 2.2 MHz. Agreement was found between the images and source beam shape, indicating an ability to map therapeutic ultrasound beams in situ. The relation between these broadband emissions, sonication amplitude, and exposure conditions are discussed.

Gain compensation technique by bias correction in arrays of Silicon Photomultipliers using fully differential fast shaper

Energy Technology Data Exchange (ETDEWEB)

Baszczyk, M., E-mail: baszczyk@agh.edu.pl [AGH University of Science and Technology, Department of Electronics, Krakow (Poland); Dorosz, P.; Glab, S.; Kucewicz, W. [AGH University of Science and Technology, Department of Electronics, Krakow (Poland); Mik, L. [AGH University of Science and Technology, Department of Electronics, Krakow (Poland); State Higher Vocational School, Tarnow (Poland); Sapor, M. [AGH University of Science and Technology, Department of Electronics, Krakow (Poland)

2016-07-11

Proposed algorithm compensates the gain by changing the bias voltage of Silicon Photomultipliers (SiPM). The signal from SiPM is amplified in fully differential preamplifier then is formed in time by the fully differential fast shaper. The compensation method was tested with four channels common cathode multi-pixel photon counter from Hamamatsu. The measurement system requires only one high voltage power supply. The polarization voltage is adjusted individually in each channel indirectly by tuning the output common mode voltage (VOCM) of fully differential amplifier. The changes of VOCM affect the input voltage through the feedback network. Actual gain of the SiPM is calculated by measuring the mean amplitude of the signal resulting from detection of single photoelectron. The VOCM is adjusted by DAC so as to reach the desired value of gain by each channel individually. The advantage of the algorithm is the possibility to set the bias of each SiPM in the array independently so they all could operate in very similar conditions (have similar gain and dark count rate). The algorithm can compensate the variations of gain of SiPM by using thermally generated pulses. There is no need to use additional current to voltage conversion which could introduce extra noises.

Gain compensation technique by bias correction in arrays of Silicon Photomultipliers using fully differential fast shaper

Science.gov (United States)

Baszczyk, M.; Dorosz, P.; Glab, S.; Kucewicz, W.; Mik, L.; Sapor, M.

2016-07-01

Proposed algorithm compensates the gain by changing the bias voltage of Silicon Photomultipliers (SiPM). The signal from SiPM is amplified in fully differential preamplifier then is formed in time by the fully differential fast shaper. The compensation method was tested with four channels common cathode multi-pixel photon counter from Hamamatsu. The measurement system requires only one high voltage power supply. The polarization voltage is adjusted individually in each channel indirectly by tuning the output common mode voltage (VOCM) of fully differential amplifier. The changes of VOCM affect the input voltage through the feedback network. Actual gain of the SiPM is calculated by measuring the mean amplitude of the signal resulting from detection of single photoelectron. The VOCM is adjusted by DAC so as to reach the desired value of gain by each channel individually. The advantage of the algorithm is the possibility to set the bias of each SiPM in the array independently so they all could operate in very similar conditions (have similar gain and dark count rate). The algorithm can compensate the variations of gain of SiPM by using thermally generated pulses. There is no need to use additional current to voltage conversion which could introduce extra noises.

Gain compensation technique by bias correction in arrays of Silicon Photomultipliers using fully differential fast shaper

International Nuclear Information System (INIS)

Baszczyk, M.; Dorosz, P.; Glab, S.; Kucewicz, W.; Mik, L.; Sapor, M.

2016-01-01

Proposed algorithm compensates the gain by changing the bias voltage of Silicon Photomultipliers (SiPM). The signal from SiPM is amplified in fully differential preamplifier then is formed in time by the fully differential fast shaper. The compensation method was tested with four channels common cathode multi-pixel photon counter from Hamamatsu. The measurement system requires only one high voltage power supply. The polarization voltage is adjusted individually in each channel indirectly by tuning the output common mode voltage (VOCM) of fully differential amplifier. The changes of VOCM affect the input voltage through the feedback network. Actual gain of the SiPM is calculated by measuring the mean amplitude of the signal resulting from detection of single photoelectron. The VOCM is adjusted by DAC so as to reach the desired value of gain by each channel individually. The advantage of the algorithm is the possibility to set the bias of each SiPM in the array independently so they all could operate in very similar conditions (have similar gain and dark count rate). The algorithm can compensate the variations of gain of SiPM by using thermally generated pulses. There is no need to use additional current to voltage conversion which could introduce extra noises.

First characterization of the Hamamatsu R11265 multi-anode photomultiplier tube

International Nuclear Information System (INIS)

Calvi, M.; Cassina, L.; Giachero, A.; Gotti, C.; Maino, M.; Matteuzzi, C.; Pessina, G.

2014-01-01

The characterization of the new Hamamatsu R11265-103-M64 multi-anode photomultiplier tube is presented. The sample available in our laboratory was tested and in particular the response to single photon was extensively studied. The gain, the anode uniformity and the dark current were measured. The tube behaviour in a longitudinal magnetic field up to 100 G was studied and the gain loss due to the ageing was quantified. The characteristics and performance of the photomultiplier tube make the R11265-103-M64 particularly tailored for an application in high energy physics experiments, such as in the LHCb Ring Imaging Cherenkov (RICH) detector at LHC. - Highlights: • We tested the new Hamamatsu R11265-103-M64 multi-anode photomultiplier tube. • We studied the response to single photon, the gain and the anode uniformity. • The tube behaviour in a longitudinal magnetic field up to 100 G was studied. • The gain loss due to the aging was quantified

Characterization of Multianode Photomultiplier Tubes for a Cherenkov Detector

Science.gov (United States)

Benninghoff, Morgen; Turisini, Matteo; Kim, Andrey; Benmokhtar, Fatiha; Kubarovsky, Valery; Duquesne University Collaboration; Jefferson Lab Collaboration

2017-09-01

In the Fall of 2017, Jefferson Lab's CLAS12 (CEBAF Large Acceptance Spectrometer) detector is expecting the addition of a RICH (ring imaging Cherenkov) detector which will allow enhanced particle identification in the momentum range of 3 to 8 GeV/c. RICH detectors measure the velocity of charged particles through the detection of produced Cherenkov radiation and the reconstruction of the angle of emission. The emitted Cherenkov photons are detected by a triangular-shaped grid of 391 multianode photomultiplier tubes (MAPMTs) made by Hamamatsu. The custom readout electronics consist of MAROC (multianode read out chip) boards controlled by FPGA (Field Programmable Gate Array) boards, and adapters used to connect the MAROC boards and MAPMTs. The focus of this project is the characterization of the MAPMTs with the new front end electronics. To perform these tests, a black box setup with a picosecond diode laser was constructed with low and high voltage supplies. A highly automated procedure was developed to acquire data at different combinations of high voltage values, light intensities and readout electronics settings. Future work involves using the collected data in calibration procedures and analyzing that data to resolve the best location for each MAPMT. SULI, NSF.

Ultrafast readout of scintillating fibers using upgraded position-sensitive photomultipliers

International Nuclear Information System (INIS)

Onel, Y.

1994-01-01

Experimental results obtained with commercially available position-sensitive photomultipliers (PSPM) coupled with 0.5 mm diameter scintillating fiber arrays show some promising performances such as space resolution better than 200 μm and time resolution ∼ 1.5 ns with a detection efficiency higher than 90%. Major progress has also been recently achieved with an upgrade of a PSPM based on new grid dynode structures. Two-track spatial resolution has been studied using the upgraded PSPM. Initial studies demonstrate that two tracks separated by a minimum distance of 3 mm are resolved

Volumetric real-time imaging using a CMUT ring array.

Science.gov (United States)

Choe, Jung Woo; Oralkan, Ömer; Nikoozadeh, Amin; Gencel, Mustafa; Stephens, Douglas N; O'Donnell, Matthew; Sahn, David J; Khuri-Yakub, Butrus T

2012-06-01

A ring array provides a very suitable geometry for forward-looking volumetric intracardiac and intravascular ultrasound imaging. We fabricated an annular 64-element capacitive micromachined ultrasonic transducer (CMUT) array featuring a 10-MHz operating frequency and a 1.27-mm outer radius. A custom software suite was developed to run on a PC-based imaging system for real-time imaging using this device. This paper presents simulated and experimental imaging results for the described CMUT ring array. Three different imaging methods--flash, classic phased array (CPA), and synthetic phased array (SPA)--were used in the study. For SPA imaging, two techniques to improve the image quality--Hadamard coding and aperture weighting--were also applied. The results show that SPA with Hadamard coding and aperture weighting is a good option for ring-array imaging. Compared with CPA, it achieves better image resolution and comparable signal-to-noise ratio at a much faster image acquisition rate. Using this method, a fast frame rate of up to 463 volumes per second is achievable if limited only by the ultrasound time of flight; with the described system we reconstructed three cross-sectional images in real-time at 10 frames per second, which was limited by the computation time in synthetic beamforming.

Development of large-area silicon photomultiplier detectors for PET applications at FBK

Energy Technology Data Exchange (ETDEWEB)

Zorzi, Nicola, E-mail: zorzi@fbk.eu [Fondazione Bruno Kessler (FBK), Via Sommarive 18, I-38123 Trento Povo (Italy); Melchiorri, Mirko; Piazza, Alessandro; Piemonte, Claudio; Tarolli, Alessandro [Fondazione Bruno Kessler (FBK), Via Sommarive 18, I-38123 Trento Povo (Italy)

2011-04-21

This paper reports on the development of large-area silicon photomultiplier (SiPM) detectors specifically designed for positron emission tomography (PET) instruments. The sensors under study are monolithic arrays of two different types: a 2x2 array of {approx}4x4 mm{sup 2} elements and an 8x8 array of 1.5x1.5 mm{sup 2} pixels. These devices are characterized at wafer level by means of an automatic test procedure, consisting of current-voltage curves in forward and reverse bias. The tests allowed selection of functioning devices and evaluation of the uniformity of basic parameters. Results of the electrical characterization are reported showing that acceptable values of yield together with rather uniform distribution of parameters have been obtained. Reliability of produced SiPMs has been proved by long-term accelerated stress tests.

Development of large-area silicon photomultiplier detectors for PET applications at FBK

International Nuclear Information System (INIS)

Zorzi, Nicola; Melchiorri, Mirko; Piazza, Alessandro; Piemonte, Claudio; Tarolli, Alessandro

2011-01-01

This paper reports on the development of large-area silicon photomultiplier (SiPM) detectors specifically designed for positron emission tomography (PET) instruments. The sensors under study are monolithic arrays of two different types: a 2x2 array of ∼4x4 mm 2 elements and an 8x8 array of 1.5x1.5 mm 2 pixels. These devices are characterized at wafer level by means of an automatic test procedure, consisting of current-voltage curves in forward and reverse bias. The tests allowed selection of functioning devices and evaluation of the uniformity of basic parameters. Results of the electrical characterization are reported showing that acceptable values of yield together with rather uniform distribution of parameters have been obtained. Reliability of produced SiPMs has been proved by long-term accelerated stress tests.

Focal Plane Detectors for the Advanced Gamma-Ray Imaging System (AGIS)

Science.gov (United States)

Wagner, R. G.; Byrum, K.; Drake, G.; Funk, S.; Otte, N.; Smith, A.; Tajima, H.; Williams, D.

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. It is being designed to achieve a significant improvement in sensitivity compared to current Imaging Air Cherenkov Telescope (IACT) Arrays. One of the main requirements in order that AGIS fulfills this goal will be to achieve higher angular resolution than current IACTs. Simulations show that a substantial improvement in angular resolution may be achieved if the pixel size is reduced to 0.05 deg, i.e. two to three times smaller than for current IACT cameras. Here we present results from testing of alternatives being considered for AGIS, including both silicon photomultipliers (SiPMs) and multi-anode photomultipliers (MAPMTs).

Three-dimensional digital imaging based on shifted point-array encoding.

Science.gov (United States)

Tian, Jindong; Peng, Xiang

2005-09-10

An approach to three-dimensional (3D) imaging based on shifted point-array encoding is presented. A kind of point-array structure light is projected sequentially onto the reference plane and onto the object surface to be tested and thus forms a pair of point-array images. A mathematical model is established to formulize the imaging process with the pair of point arrays. This formulation allows for a description of the relationship between the range image of the object surface and the lateral displacement of each point in the point-array image. Based on this model, one can reconstruct each 3D range image point by computing the lateral displacement of the corresponding point on the two point-array images. The encoded point array can be shifted digitally along both the lateral and the longitudinal directions step by step to achieve high spatial resolution. Experimental results show good agreement with the theoretical predictions. This method is applicable for implementing 3D imaging of object surfaces with complex topology or large height discontinuities.

Characterization of New-Generation Silicon Photomultipliers for Nuclear Security Applications

Science.gov (United States)

Wonders, Marc A.; Chichester, David L.; Flaska, Marek

2018-01-01

Silicon photomultipliers have received a great deal of interest recently for use in applications spanning a wide variety of fields, including nuclear safeguards and nonproliferation. For nuclear-related applications, the ability of silicon photomultipliers to discriminate neutrons from gamma rays using pulse shape discrimination when coupled with certain organic scintillators is a characteristic of utmost importance. This work reports on progress characterizing the performance of twenty different silicon photomultipliers from five manufacturers with an emphasis on pulse shape discrimination performance and timing. Results are presented on pulse shape discrimination performance as a function of overvoltage for 6-mm x 6-mm silicon photomultipliers, and the time response to stilbene is characterized for silicon photomultipliers of three different sizes. Finally, comparison with a photomultiplier tube shows that some new-generation silicon photomultipliers can perform as well as photomultiplier tubes in neutron-gamma ray discrimination.

A novel readout concept for multianode photomultiplier tubes with pad matrix anode layout

Energy Technology Data Exchange (ETDEWEB)

Popov, Vladimir [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States)]. E-mail: Popov@jlab.org; Majewski, Stan [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Welch, Benjamin L. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States)

2006-11-01

We have developed a new analog readout concept for multianode photomultiplier tubes with a pad matrix anode layout. This new readout technique is the result of a modification of a technique previously developed at the Detector Group of Jefferson Lab (V. Popov, US patent No: 6,747,263 B1) [V. Popov, S. Majewski, A.G. Weisenberger, Readout Electronics for Multianode Photomultiplier Tubes with Pad Matrix Anode Layout, Thomas Jefferson National Accelerator Facility, IEEE 2003 Medical Imaging Conference Record, November 2003]. The new analog readout circuit provides the same analog conversion of matrix 2-D output into X and Y projective output with a significant reduction of analog outputs. The old readout network consists of resistors' matrix and current collecting amplifiers, and it provides decoupling of each anode output into two directions (one to X and one to Y coordinates), but a decoupling function that is carried out independent of photomultiplier tube gains nonuniformity. A newly developed readout network (US patent pending) also consists of resistors' matrix and current collecting amplifiers, but the new matrix includes an additional dumping resistor that provides an excess current from anode pad grounding. As a result, we subtract an extra current of high-gain pads in order to move the pads gain to an absolute minimum value for a given photomultiplier tube. This gain equalization procedure reduces image distortion related to gain nonuniformity. The new readout technique was used in several new radiation imaging detectors designed in the Detector Group of Jefferson Lab. It shows a visible readout uniformity and linearity improvement. The test results of an initial evaluation of this readout that is applied for data readout of four H8500 Hamamtsu PSPMT are presented.

Characterization of New-Generation Silicon Photomultipliers for Nuclear Security Applications

Directory of Open Access Journals (Sweden)

Wonders Marc A.

2018-01-01

Full Text Available Silicon photomultipliers have received a great deal of interest recently for use in applications spanning a wide variety of fields, including nuclear safeguards and nonproliferation. For nuclear-related applications, the ability of silicon photomultipliers to discriminate neutrons from gamma rays using pulse shape discrimination when coupled with certain organic scintillators is a characteristic of utmost importance. This work reports on progress characterizing the performance of twenty different silicon photomultipliers from five manufacturers with an emphasis on pulse shape discrimination performance and timing. Results are presented on pulse shape discrimination performance as a function of overvoltage for 6-mm x 6-mm silicon photomultipliers, and the time response to stilbene is characterized for silicon photomultipliers of three different sizes. Finally, comparison with a photomultiplier tube shows that some new-generation silicon photomultipliers can perform as well as photomultiplier tubes in neutron-gamma ray discrimination.

Advances in CMOS solid-state photomultipliers for scintillation detector applications

Energy Technology Data Exchange (ETDEWEB)

Christian, James F.; Stapels, Christopher J.; Johnson, Erik B.; McClish, Mickel; Dokhale, Purushotthom; Shah, Kanai S.; Mukhopadhyay, Sharmistha; Chapman, Eric [Radiation Monitoring Devices, 44 Hunt Street, Watertownm, MA 02472 (United States); Augustine, Frank L., E-mail: JChristian@RMDInc.co [Augustine Engineering, 2115 Park Dale Ln, Encinitas, CA 92024 (United States)

2010-12-11

Solid-state photomultipliers (SSPMs) are a compact, lightweight, potentially low-cost alternative to a photomultiplier tube for a variety of scintillation detector applications, including digital-dosimeter and medical-imaging applications. Manufacturing SSPMs with a commercial CMOS process provides the ability for rapid prototyping, and facilitates production to reduce the cost. RMD designs CMOS SSPM devices that are fabricated by commercial foundries. This work describes the characterization and performance of these devices for scintillation detector applications. This work also describes the terms contributing to device noise in terms of the excess noise of the SSPM, the binomial statistics governing the number of pixels triggered by a scintillation event, and the background, or thermal, count rate. The fluctuations associated with these terms limit the resolution of the signal pulse amplitude. We explore the use of pixel-level signal conditioning, and characterize the performance of a prototype SSPM device that preserves the digital nature of the signal. In addition, we explore designs of position-sensitive SSPM detectors for medical imaging applications, and characterize their performance.

Development of 2D-ACAR apparatus using position-sensitive photomultiplier tubes

Energy Technology Data Exchange (ETDEWEB)

Nagai, Yasuyoshi; Saito, Haruo; Iwata, Tetsuya; Nagashima, Yasuyuki; Hyodo, Toshio [Tokyo Univ. (Japan). Coll. of Arts and Sciences; Uchida, Hiroshi; Omura, Tomohide

1997-03-01

A new two-dimensional angular correlation of annihilation radiation apparatus is described. Position-sensitive photomultiplier tubes coupled with two-dimensional arrays of small BGO scintillator blocks make simple and compact position-sensitive {gamma}-ray detectors. With a sample-detector distance of 5m, an angular resolution of 1.1 mrad FWHM and a coincidence count rate of {approx}2.4 c.p.s. per mCi are obtained. Its performance is demonstrated by the result of a test measurement for KI crystal in which non-localized positronium exists at low temperatures. (author)

Silicon photomultiplier as a detector of Cherenkov photons

International Nuclear Information System (INIS)

Korpar, S.; Dolenec, R.; Hara, K.; Iijima, T.; Krizan, P.; Mazuka, Y.; Pestotnik, R.; Stanovnik, A.; Yamaoka, M.

2008-01-01

A novel photon detector-i.e. the silicon photomultiplier-whose main advantage over conventional photomultiplier tubes is the operation in high magnetic fields, has been tested as a photon detector in a proximity focusing RICH with aerogel radiator. This type of RICH counter is proposed for the upgrade of the Belle detector at the KEK B-factory. Recently produced silicon photomultipliers show less noise and have larger size, which are important issues for a large area photon detector. We measured the single photon pulse height distribution, the timing resolution and the position sensitivity for different silicon photomultipliers (Hamamatsu MPPC HC025, HC050, and HC100). The silicon photomultipliers were then used to detect Cherenkov photons emitted by cosmic ray particles in a proximity focusing aerogel RICH. Various light guides were investigated in order to increase the detection efficiency

A new DOI detector design using discrete crystal array with depth-dependent reflector patterns and single-ended readout

Energy Technology Data Exchange (ETDEWEB)

Lee, Seung-Jae; Lee, Chaeyeong [Department of Radiological Science, Yonsei University, Wonju 26493 (Korea, Republic of); Kang, Jihoon, E-mail: ray.jihoon.kang@gmail.com [Department of Biomedical Engineering, Chonnam National University, 50 Daehak-ro, Yeosu, Jeonnam 59626 (Korea, Republic of); Chung, Yong Hyun, E-mail: ychung@yonsei.ac.kr [Department of Radiological Science, Yonsei University, Wonju 26493 (Korea, Republic of)

2017-01-21

We developed a depth of interaction (DOI) positron emission tomography (PET) detector using depth-dependent reflector patterns in a discrete crystal array. Due to the different reflector patterns at depth, light distribution was changed relative to depth. As a preliminary experiment, we measured DOI detector module crystal identification performance. The crystal consisted of a 9×9 array of 2 mmx2 mmx20 mm lutetium-yttrium oxyorthosilicate (LYSO) crystals. The crystal array was optically coupled to a 64-channel position-sensitive photomultiplier tube with a 2 mmx2 mm anode size and an 18.1 mmx18.1 mm effective area. We obtained the flood image with an Anger-type calculation. DOI layers and 9×9 pixels were well distinguished in the obtained images. Preclinical PET scanners based on this detector design offer the prospect of high and uniform spatial resolution.

A new DOI detector design using discrete crystal array with depth-dependent reflector patterns and single-ended readout

International Nuclear Information System (INIS)

Lee, Seung-Jae; Lee, Chaeyeong; Kang, Jihoon; Chung, Yong Hyun

2017-01-01

We developed a depth of interaction (DOI) positron emission tomography (PET) detector using depth-dependent reflector patterns in a discrete crystal array. Due to the different reflector patterns at depth, light distribution was changed relative to depth. As a preliminary experiment, we measured DOI detector module crystal identification performance. The crystal consisted of a 9×9 array of 2 mmx2 mmx20 mm lutetium-yttrium oxyorthosilicate (LYSO) crystals. The crystal array was optically coupled to a 64-channel position-sensitive photomultiplier tube with a 2 mmx2 mm anode size and an 18.1 mmx18.1 mm effective area. We obtained the flood image with an Anger-type calculation. DOI layers and 9×9 pixels were well distinguished in the obtained images. Preclinical PET scanners based on this detector design offer the prospect of high and uniform spatial resolution.

GEM-based gaseous photomultipliers for UV and visible photon imaging

International Nuclear Information System (INIS)

Moermann, D.; Balcerzyk, M.; Breskin, A.; Chechik, R.; Singh, B.K.; Buzulutskov, A.

2003-01-01

We present the current status of our research on GEM-based gaseous photomultipliers. Detectors combining multi-GEM electron multipliers with semi-transparent and reflective photocathodes are discussed. We present recent progress in extending the sensitivity of these detectors into the visible range. We demonstrate the long-term stability of an argon-sealed bi-alkali photo-diode and provide preliminary results of a gas-sealed Kapton-GEM detector with a bi-alkali photocathode. The problem of ion-induced secondary electron emission is addressed

Silicon photomultipliers in AMIGA muon counters

Energy Technology Data Exchange (ETDEWEB)

Botti, Ana Martina [Institut fuer Kernphysik, Karlsruher Institut fuer Technologie (Germany); Instituto de Tecnologias en Deteccion y Astroparticulas (ITeDA) (Argentina); Collaboration: Pierre-Auger-Collaboration

2016-07-01

The project AMIGA (Auger Muons and Infill for the Ground Array) aims to extend the energy range at the Pierre Auger Observatory to observe cosmic rays of lower energies (down to ∝10{sup 17} eV) and to study the transition from extragalactic to galactic cosmic rays. AMIGA is compounded by an infill of surface detectors (employing Cherenkov radiation detection in water) and muon counters. The AMIGA muon counters consist of an array of buried modules composed of 64 scintillator bars, a multi-pixel Photo Multiplier Tube (PMT) and the corresponding electronic of acquisition which works along with the surface detector. Currently, ITeDA is evaluating the feasibility of replacing PMTs with silicon photomultipliers (SiPM) without performing any substantial modification in the digital readout nor in the mechanical design. I present calibration results of a prototype module associated to the surface detector Toune of the Pierre Auger Observatory using a SiPM Hamamatsu S1257-100C plugged to the standard AMIGA front-end electronics. In addition, a study concerning gain stability and temperature variation has also been performed and is reported. I finally discuss a comparison between traces measured by both photodetectors (PMT and SiPM) for modules associated to the surface detector Toune.

Coded aperture imaging with uniformly redundant arrays

International Nuclear Information System (INIS)

Fenimore, E.E.; Cannon, T.M.

1980-01-01

A system is described which uses uniformly redundant arrays to image non-focusable radiation. The array is used in conjunction with a balanced correlation technique to provide a system with no artifacts so that virtually limitless signal-to-noise ratio is obtained with high transmission characteristics. The array is mosaicked to reduce required detector size over conventional array detectors. 15 claims

Two-dimensional random arrays for real time volumetric imaging

DEFF Research Database (Denmark)

Davidsen, Richard E.; Jensen, Jørgen Arendt; Smith, Stephen W.

1994-01-01

real time volumetric imaging system, which employs a wide transmit beam and receive mode parallel processing to increase image frame rate. Depth-of-field comparisons were made from simulated on-axis and off-axis beamplots at ranges from 30 to 160 mm for both coaxial and offset transmit and receive......Two-dimensional arrays are necessary for a variety of ultrasonic imaging techniques, including elevation focusing, 2-D phase aberration correction, and real time volumetric imaging. In order to reduce system cost and complexity, sparse 2-D arrays have been considered with element geometries...... selected ad hoc, by algorithm, or by random process. Two random sparse array geometries and a sparse array with a Mills cross receive pattern were simulated and compared to a fully sampled aperture with the same overall dimensions. The sparse arrays were designed to the constraints of the Duke University...

Scintillation probe with photomultiplier tube saturation indicator

International Nuclear Information System (INIS)

Ruch, J.F.; Urban, D.J.

1996-01-01

A photomultiplier tube saturation indicator is formed by supplying a supplemental light source, typically an light emitting diode (LED), adjacent to the photomultiplier tube. A switch allows the light source to be activated. The light is forwarded to the photomultiplier tube by an optical fiber. If the probe is properly light tight, then a meter attached to the indicator will register the light from the LED. If the probe is no longer light tight, and the saturation indicator is saturated, no signal will be registered when the LED is activated. 2 figs

Precise analysis of the metal package photomultiplier single photoelectron spectra

International Nuclear Information System (INIS)

Chirikov-Zorin, I.E.; Fedorko, I.; Sykora, I.; Tokar, S.; Menzione, A.

2000-01-01

A deconvolution method based on a sophisticated photomultiplier response function was used to analyse the compact metal package photomultiplier spectra taken in single photoelectron mode. The spectra taken by Hamamtsu R5600 and R5900 photomultipliers have been analysed. The detailed analysis shows that the method appropriately describes the process of charge multiplication in these photomultipliers in a wide range of working regimes and the deconvoluted parameters are established with about 1% accuracy. The method can be used for a detailed analysis of photomultiplier noise and for calibration purposes

Flat dielectric metasurface lens array for three dimensional integral imaging

Science.gov (United States)

Zhang, Jianlei; Wang, Xiaorui; Yang, Yi; Yuan, Ying; Wu, Xiongxiong

2018-05-01

In conventional integral imaging, the singlet refractive lens array limits the imaging performance due to its prominent aberrations. Different from the refractive lens array relying on phase modulation via phase change accumulated along the optical paths, metasurfaces composed of nano-scatters can produce phase abrupt over the scale of wavelength. In this letter, we propose a novel lens array consisting of two neighboring flat dielectric metasurfaces for integral imaging system. The aspherical phase profiles of the metasurfaces are optimized to improve imaging performance. The simulation results show that our designed 5 × 5 metasurface-based lens array exhibits high image quality at designed wavelength 865 nm.

Photoacoustic projection imaging using an all-optical detector array

Science.gov (United States)

Bauer-Marschallinger, J.; Felbermayer, K.; Berer, T.

2018-02-01

We present a prototype for all-optical photoacoustic projection imaging. By generating projection images, photoacoustic information of large volumes can be retrieved with less effort compared to common photoacoustic computed tomography where many detectors and/or multiple measurements are required. In our approach, an array of 60 integrating line detectors is used to acquire photoacoustic waves. The line detector array consists of fiber-optic MachZehnder interferometers, distributed on a cylindrical surface. From the measured variation of the optical path lengths of the interferometers, induced by photoacoustic waves, a photoacoustic projection image can be reconstructed. The resulting images represent the projection of the three-dimensional spatial light absorbance within the imaged object onto a two-dimensional plane, perpendicular to the line detector array. The fiber-optic detectors achieve a noise-equivalent pressure of 24 Pascal at a 10 MHz bandwidth. We present the operational principle, the structure of the array, and resulting images. The system can acquire high-resolution projection images of large volumes within a short period of time. Imaging large volumes at high frame rates facilitates monitoring of dynamic processes.

Pattern recognition trigger electronics for an imaging atmospheric Cherenkov telescope

International Nuclear Information System (INIS)

Bradbury, S.M.; Rose, H.J.

2002-01-01

For imaging atmospheric Cherenkov telescopes, which aim to detect electromagnetic air showers with cameras consisting of several hundred photomultiplier pixels, the single pixel trigger rate is dominated by fluctuations in night sky brightness and by ion feedback in the photomultipliers. Pattern recognition trigger electronics may be used to reject night sky background images, thus reducing the data rate to a manageable level. The trigger system described here detects patterns of 2, 3 or 4 adjacent pixel signals within a 331 pixel camera and gives a positive trigger decision in 65 ns. The candidate pixel pattern is compared with the contents of a pre-programmed memory. With the trigger decision timing controlled by a fixed delay the time-jitter inherent in the use of programmable gate arrays is avoided. This system is now in routine operation at the Whipple 10 m Telescope

Fast disk array for image storage

Science.gov (United States)

Feng, Dan; Zhu, Zhichun; Jin, Hai; Zhang, Jiangling

1997-01-01

A fast disk array is designed for the large continuous image storage. It includes a high speed data architecture and the technology of data striping and organization on the disk array. The high speed data path which is constructed by two dual port RAM and some control circuit is configured to transfer data between a host system and a plurality of disk drives. The bandwidth can be more than 100 MB/s if the data path based on PCI (peripheral component interconnect). The organization of data stored on the disk array is similar to RAID 4. Data are striped on a plurality of disk, and each striping unit is equal to a track. I/O instructions are performed in parallel on the disk drives. An independent disk is used to store the parity information in the fast disk array architecture. By placing the parity generation circuit directly on the SCSI (or SCSI 2) bus, the parity information can be generated on the fly. It will affect little on the data writing in parallel on the other disks. The fast disk array architecture designed in the paper can meet the demands of the image storage.

2D sparse array transducer optimization for 3D ultrasound imaging

International Nuclear Information System (INIS)

Choi, Jae Hoon; Park, Kwan Kyu

2014-01-01

A 3D ultrasound image is desired in many medical examinations. However, the implementation of a 2D array, which is needed for a 3D image, is challenging with respect to fabrication, interconnection and cabling. A 2D sparse array, which needs fewer elements than a dense array, is a realistic way to achieve 3D images. Because the number of ways the elements can be placed in an array is extremely large, a method for optimizing the array configuration is needed. Previous research placed the target point far from the transducer array, making it impossible to optimize the array in the operating range. In our study, we focused on optimizing a 2D sparse array transducer for 3D imaging by using a simulated annealing method. We compared the far-field optimization method with the near-field optimization method by analyzing a point-spread function (PSF). The resolution of the optimized sparse array is comparable to that of the dense array.

Replacement of a photomultiplier tube in a 2-inch thallium-doped sodium iodide gamma spectrometer with silicon photomultipliers and a light guide

Directory of Open Access Journals (Sweden)

Chankyu Kim

2015-06-01

Full Text Available The thallium-doped sodium iodide [NaI(Tl] scintillation detector is preferred as a gamma spectrometer in many fields because of its general advantages. A silicon photomultiplier (SiPM has recently been developed and its application area has been expanded as an alternative to photomultiplier tubes (PMTs. It has merits such as a low operating voltage, compact size, cheap production cost, and magnetic resonance compatibility. In this study, an array of SiPMs is used to develop an NaI(Tl gamma spectrometer. To maintain detection efficiency, a commercial NaI(Tl 2′ × 2′ scintillator is used, and a light guide is used for the transport and collection of generated photons from the scintillator to the SiPMs without loss. The test light guides were fabricated with polymethyl methacrylate and reflective materials. The gamma spectrometer systems were set up and included light guides. Through a series of measurements, the characteristics of the light guides and the proposed gamma spectrometer were evaluated. Simulation of the light collection was accomplished using the DETECT 97 code (A. Levin, E. Hoskinson, and C. Moison, University of Michigan, USA to analyze the measurement results. The system, which included SiPMs and the light guide, achieved 14.11% full width at half maximum energy resolution at 662 keV.

Modeling crosstalk in silicon photomultipliers

International Nuclear Information System (INIS)

Gallego, L; Rosado, J; Blanco, F; Arqueros, F

2013-01-01

Optical crosstalk seriously limits the photon-counting resolution of silicon photomultipliers. In this work, realistic analytical models to describe the crosstalk effects on the response of these photodetectors are presented and compared with experimental data. The proposed models are based on the hypothesis that each pixel of the array has a finite number of available neighboring pixels to excite via crosstalk. Dead-time effects and geometrical aspects of the propagation of crosstalk between neighbors are taken into account in the models for different neighborhood configurations. Simple expressions to account for crosstalk effects on the pulse-height spectrum as well as to evaluate the excess noise factor due to crosstalk are also given. Dedicated measurements were carried out under both dark-count conditions and pulsed illumination. Moreover, the influence of afterpulsing on the measured pulse-height spectrum was studied, and a measurement of the recovery time of pixels was reported. High-resolution pulse-height spectra were obtained by means of a detailed waveform analysis, and the results have been used to validate our crosstalk models.

First results of systematic studies done with silicon photomultipliers

International Nuclear Information System (INIS)

Bosio, C.; Gentile, S.; Kuznetsova, E.; Meddi, F.

2008-01-01

Multicell avalanche photodiode structure operated in Geiger mode usually referred as silicon photomultiplier is a new intensively developing technology for photon detection. Insensitivity to magnetic fields, low operation voltage and small size make silicon photomultipliers very attractive for high-energy physics, astrophysics and medical applications. The presented results are obtained during the first steps taken in order to develop a setup and measurement procedures which allow to compare properties of diverse samples of silicon photomultipliers available on market. The response to low-intensity light was studied for silicon photomultipliers produced by CPTA (Russia), Hamamatsu (Japan), ITC-irst (Italy) and SensL (Ireland).

The first telescope of the HEGRA air Cherenkov imaging telescope array

International Nuclear Information System (INIS)

Mirzoyan, R.; Kankanian, R.; Krennrich, F.; Mueller, N.; Sander, H.; Sawallisch, P.; Aharonian, F.; Akhperjanian, A.; Beglarian, A.; Fernandez, J.; Fonseca, V.; Grewe, W.; Heusler, A.; Konopelko, A.K.; Lorenz, E.; Merck, M.; Plyasheshnikov, A.V.; Renker, D.; Samorski, M.; Sauerland, K.; Smarsch, E.; Stamm, W.; Ulrich, M.; Wiedner, C.A.; Wirth, H.

1994-01-01

In search of VHE γ ray emission from cosmic point sources a system of imaging Cherenkov telescopes is constructed at present on the Canarian island of La Palma; the first telescope has been operational since 1992. The Cherenkov light from air shower particles is collected by a 5 m 2 reflector. The camera at the focus contains 37 photomultipliers which sample the images of the Cherenkov flashes. The subsequent image analysis allows the discrimination of γ ray induced events from the much more abundant charged cosmic ray induced showers. The telescope has an effective energy threshold for γ showers of about 1.5 TeV. During the first year of operation a signal from the Crab nebula was detected. ((orig.))

INFN Camera demonstrator for the Cherenkov Telescope Array

CERN Document Server

Ambrosi, G; Aramo, C.; Bertucci, B.; Bissaldi, E.; Bitossi, M.; Brasolin, S.; Busetto, G.; Carosi, R.; Catalanotti, S.; Ciocci, M.A.; Consoletti, R.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; de Palma, F.; Desiante, R.; Di Girolamo, T.; Di Giulio, C.; Doro, M.; D'Urso, D.; Ferraro, G.; Ferrarotto, F.; Gargano, F.; Giglietto, N.; Giordano, F.; Giraudo, G.; Iacovacci, M.; Ionica, M.; Iori, M.; Longo, F.; Mariotti, M.; Mastroianni, S.; Minuti, M.; Morselli, A.; Paoletti, R.; Pauletta, G.; Rando, R.; Fernandez, G. Rodriguez; Rugliancich, A.; Simone, D.; Stella, C.; Tonachini, A.; Vallania, P.; Valore, L.; Vagelli, V.; Verzi, V.; Vigorito, C.

2015-01-01

The Cherenkov Telescope Array is a world-wide project for a new generation of ground-based Cherenkov telescopes of the Imaging class with the aim of exploring the highest energy region of the electromagnetic spectrum. With two planned arrays, one for each hemisphere, it will guarantee a good sky coverage in the energy range from a few tens of GeV to hundreds of TeV, with improved angular resolution and a sensitivity in the TeV energy region better by one order of magnitude than the currently operating arrays. In order to cover this wide energy range, three different telescope types are envisaged, with different mirror sizes and focal plane features. In particular, for the highest energies a possible design is a dual-mirror Schwarzschild-Couder optical scheme, with a compact focal plane. A silicon photomultiplier (SiPM) based camera is being proposed as a solution to match the dimensions of the pixel (angular size of ~ 0.17 degrees). INFN is developing a camera demonstrator made by 9 Photo Sensor Modules (PSMs...

Silicon photomultipliers for positron emission tomography detectors with depth of interaction encoding capability

International Nuclear Information System (INIS)

Taghibakhsh, Farhad; Reznik, Alla; Rowlands, John A.

2011-01-01

Silicon photomultipliers (SiPMs) are receiving increasing attention in the field of positron emission tomography (PET) detectors. Compared to photomultiplier tubes, they offer novel detector configurations for the extraction of depth of interaction (DOI) information, or enable emerging medical imaging modalities such as simultaneous PET-magnetic resonant imaging (MRI). In this article, we used 2x2x20 mm 3 LYSO scintillator crystals coupled to SiPMs on both ends (dual-ended readout configuration) to evaluate the detector performance for DOI-PET applications. We investigated the effect of scintillator crystal surface finishing on sensitivity and resolution of DOI, as well as on energy and timing resolution. Measurements indicate DOI sensitivity and resolution of 7.1% mm -1 and 2.1±0.6 mm for saw-cut, and 1.3% mm -1 and 9.0±1.5 mm, for polished scintillator crystals, respectively. Energy resolution varies from 19% when DOI is in the center, to 15% with DOI at either end of the saw-cut crystal, while it remains constant at ∼14% for polished scintillators. Based on our results we conclude that 2x2x20 mm 3 saw-cut (without any special side wall polishing) LYSO crystals coupled to 2x2 mm 2 silicon photomultipliers are optimal for isotropic 2 mm resolution DOI-PET applications.

Cherenkov luminescence measurements with digital silicon photomultipliers: a feasibility study

Energy Technology Data Exchange (ETDEWEB)

Ciarrocchi, Esther; Belcari, Nicola; Guerra, Alberto Del [Department of Physics, University of Pisa, Pisa (Italy); INFN, section of Pisa, Pisa (Italy); Cherry, Simon R. [Department of Biomedical Engineering, University of California, Davis, CA (United States); Lehnert, Adrienne; Hunter, William C. J.; McDougald, Wendy; Miyaoka, Robert S.; Kinahan, Paul E. [Department of Radiology, University of Washington, Seattle, WA (United States)

2015-11-16

A feasibility study was done to assess the capability of digital silicon photomultipliers to measure the Cherenkov luminescence emitted by a β source. Cherenkov luminescence imaging (CLI) is possible with a charge coupled device (CCD) based technology, but a stand-alone technique for quantitative activity measurements based on Cherenkov luminescence has not yet been developed. Silicon photomultipliers (SiPMs) are photon counting devices with a fast impulse response and can potentially be used to quantify β-emitting radiotracer distributions by CLI. In this study, a Philips digital photon counting (PDPC) silicon photomultiplier detector was evaluated for measuring Cherenkov luminescence. The PDPC detector is a matrix of avalanche photodiodes, which were read one at a time in a dark count map (DCM) measurement mode (much like a CCD). This reduces the device active area but allows the information from a single avalanche photodiode to be preserved, which is not possible with analog SiPMs. An algorithm to reject the noisiest photodiodes and to correct the measured count rate for the dark current was developed. The results show that, in DCM mode and at (10–13) °C, the PDPC has a dynamic response to different levels of Cherenkov luminescence emitted by a β source and transmitted through an opaque medium. This suggests the potential for this approach to provide quantitative activity measurements. Interestingly, the potential use of the PDPC in DCM mode for direct imaging of Cherenkov luminescence, as a opposed to a scalar measurement device, was also apparent. We showed that a PDPC tile in DCM mode is able to detect and image a β source through its Cherenkov radiation emission. The detector’s dynamic response to different levels of radiation suggests its potential quantitative capabilities, and the DCM mode allows imaging with a better spatial resolution than the conventional event-triggered mode. Finally, the same acquisition procedure and data processing could

Cherenkov luminescence measurements with digital silicon photomultipliers: a feasibility study

International Nuclear Information System (INIS)

Ciarrocchi, Esther; Belcari, Nicola; Guerra, Alberto Del; Cherry, Simon R.; Lehnert, Adrienne; Hunter, William C. J.; McDougald, Wendy; Miyaoka, Robert S.; Kinahan, Paul E.

2015-01-01

A feasibility study was done to assess the capability of digital silicon photomultipliers to measure the Cherenkov luminescence emitted by a β source. Cherenkov luminescence imaging (CLI) is possible with a charge coupled device (CCD) based technology, but a stand-alone technique for quantitative activity measurements based on Cherenkov luminescence has not yet been developed. Silicon photomultipliers (SiPMs) are photon counting devices with a fast impulse response and can potentially be used to quantify β-emitting radiotracer distributions by CLI. In this study, a Philips digital photon counting (PDPC) silicon photomultiplier detector was evaluated for measuring Cherenkov luminescence. The PDPC detector is a matrix of avalanche photodiodes, which were read one at a time in a dark count map (DCM) measurement mode (much like a CCD). This reduces the device active area but allows the information from a single avalanche photodiode to be preserved, which is not possible with analog SiPMs. An algorithm to reject the noisiest photodiodes and to correct the measured count rate for the dark current was developed. The results show that, in DCM mode and at (10–13) °C, the PDPC has a dynamic response to different levels of Cherenkov luminescence emitted by a β source and transmitted through an opaque medium. This suggests the potential for this approach to provide quantitative activity measurements. Interestingly, the potential use of the PDPC in DCM mode for direct imaging of Cherenkov luminescence, as a opposed to a scalar measurement device, was also apparent. We showed that a PDPC tile in DCM mode is able to detect and image a β source through its Cherenkov radiation emission. The detector’s dynamic response to different levels of radiation suggests its potential quantitative capabilities, and the DCM mode allows imaging with a better spatial resolution than the conventional event-triggered mode. Finally, the same acquisition procedure and data processing could

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.

Vision communications based on LED array and imaging sensor

Science.gov (United States)

Yoo, Jong-Ho; Jung, Sung-Yoon

2012-11-01

In this paper, we propose a brand new communication concept, called as "vision communication" based on LED array and image sensor. This system consists of LED array as a transmitter and digital device which include image sensor such as CCD and CMOS as receiver. In order to transmit data, the proposed communication scheme simultaneously uses the digital image processing and optical wireless communication scheme. Therefore, the cognitive communication scheme is possible with the help of recognition techniques used in vision system. By increasing data rate, our scheme can use LED array consisting of several multi-spectral LEDs. Because arranged each LED can emit multi-spectral optical signal such as visible, infrared and ultraviolet light, the increase of data rate is possible similar to WDM and MIMO skills used in traditional optical and wireless communications. In addition, this multi-spectral capability also makes it possible to avoid the optical noises in communication environment. In our vision communication scheme, the data packet is composed of Sync. data and information data. Sync. data is used to detect the transmitter area and calibrate the distorted image snapshots obtained by image sensor. By making the optical rate of LED array be same with the frame rate (frames per second) of image sensor, we can decode the information data included in each image snapshot based on image processing and optical wireless communication techniques. Through experiment based on practical test bed system, we confirm the feasibility of the proposed vision communications based on LED array and image sensor.

Photomultiplier tubes for Low Level Cerenkov Detectors

Energy Technology Data Exchange (ETDEWEB)

Strindehag, O

1965-03-15

Tube backgrounds of several 2-inch photomultiplier types having S11, 'S' , S13 and S20 cathodes are compared by measuring signal and background pulse height distributions at pulse heights corresponding to a few photo-electrons. The reference signal is generated by means of a {beta}-source and a plexiglass radiator. It is found that comparatively good results are obtained with selected tubes of the EMI types 6097B and 9514B having equivalent dark current dc values down to 10{sup -12} input lumens. Special interest is devoted to the correlation between the measured tube backgrounds and the dark current dc values of the tubes, as a good correlation between these parameters simplifies the selection of photomultiplier tubes. The equivalent dark currents of the tested tubes extend over the range 10{sup -12} to 10{sup -9} input lumens. Although the investigation deals with photomultiplier tubes intended for use in low level Cerenkov detectors it is believed that the results could be valuable in other fields where photomultiplier tubes are utilized for the detection of weak light pulses.

Photomultiplier tubes for Low Level Cerenkov Detectors

International Nuclear Information System (INIS)

Strindehag, O.

1965-03-01

Tube backgrounds of several 2-inch photomultiplier types having S11, 'S' , S13 and S20 cathodes are compared by measuring signal and background pulse height distributions at pulse heights corresponding to a few photo-electrons. The reference signal is generated by means of a β-source and a plexiglass radiator. It is found that comparatively good results are obtained with selected tubes of the EMI types 6097B and 9514B having equivalent dark current dc values down to 10 -12 input lumens. Special interest is devoted to the correlation between the measured tube backgrounds and the dark current dc values of the tubes, as a good correlation between these parameters simplifies the selection of photomultiplier tubes. The equivalent dark currents of the tested tubes extend over the range 10 -12 to 10 -9 input lumens. Although the investigation deals with photomultiplier tubes intended for use in low level Cerenkov detectors it is believed that the results could be valuable in other fields where photomultiplier tubes are utilized for the detection of weak light pulses

Volumetric Real-Time Imaging Using a CMUT Ring Array

OpenAIRE

Choe, Jung Woo; Oralkan, Ömer; Nikoozadeh, Amin; Gencel, Mustafa; Stephens, Douglas N.; O’Donnell, Matthew; Sahn, David J.; Khuri-Yakub, Butrus T.

2012-01-01

A ring array provides a very suitable geometry for forward-looking volumetric intracardiac and intravascular ultrasound imaging. We fabricated an annular 64-element capacitive micromachined ultrasonic transducer (CMUT) array featuring a 10-MHz operating frequency and a 1.27-mm outer radius. A custom software suite was developed to run on a PC-based imaging system for real-time imaging using this device.

A gas proportional scintillation counter for use in large area detector systems without photomultipliers

International Nuclear Information System (INIS)

Baruch, J.E.F.; Brooke, G.; Kellermann, E.W.; Bateman, J.E.; Connolly, J.F.

1978-03-01

The properties of a prototype gas proportional scintillation detector, for use in large numbers, are examined. The detector is designed to focus a light signal, which is proportional to ionisation loss, into a fibre optic lightguide. It is shown that a single charged particle traversing the detector produces enough light out of the lightguide to be seen by a TV camera. Problems of lifetime and large scale detector production are discussed. Properties of saturation, linearity, position sensitivity, and operating limits are examined. It is shown that an array of gas proportional scintillation detectors when used with fibre optic lightguides and TV camera readout could offer significant improvements in cost per area and reliability over a scintillator plus photomultiplier or a wire proportional chamber array. (author)

Final Technical Report Radiation Hard Tight Pitch GaInP SPAD Arrays for High Energy Physics

Energy Technology Data Exchange (ETDEWEB)

Harmon, Eric

2018-01-26

The specialized photodetectors used in high energy physics experiments often need to remain extremely sensitive for years despite radiation induced damage caused by the constant bombardment of high energy particles. To solve this problem, LightSpin Technologies, Inc. in collaboration with Prof. Bradley Cox and the University of Virginia is developing radiation-hard GaInP photodetectors which are projected to be extraordinarily radiation hard, theoretically capable of withstanding a 100,000-fold higher radiation dose than silicon. In this Phase I SBIR project, LightSpin investigated the performance and radiation hardness of fifth generation GaInP SPAD arrays. These fifth generation devices used a new planar processing approach that enables very tight pitch arrays to be produced. High performance devices with SPAD pitches of 11, 15, and 25 μm were successfully demonstrated, which greatly increased the dynamic range and maximum count rate of the devices. High maximum count rates are critical when considering radiation hardness, since radiation damage causes a proportional increase in the dark count rate, causing SPAD arrays with low maximum count rates (large SPAD pitches) to fail. These GaInP SPAD array Photomultiplier Chips™ were irradiated with protons, electrons, and neutrons. Initial irradiation results were disappointing, with the post-irradiation devices exhibiting excessively high dark currents. The degradation was traced to surface leakage currents that were largely eliminated through the use of trenches etched around the exterior of the Photomultiplier Chip™ (not between SPAD elements). A second round of irradiations on Photomultiplier Chips™ with trenches proved substantially more successful, with post-irradiation dark currents remaining relatively low, though dark count rates were observed to increase at the highest doses. Preliminary analysis of the post-irradiation devices is promising … many of the irradiated Photomultiplier Chips™ still

Timing coincidence studies with fast photomultipliers

International Nuclear Information System (INIS)

Raoof, M.A.; Raoof, S.A.

1981-01-01

The time response of RCA C70045D photomultipliers was studied using a subnanosecond light flasher. The tubes, which have an output rise time of approximately 0.5 ns, were used in coincidence to study the variations in the fwhm of the time spectrum over a certain dynamic range of pulse amplitudes for both leading edge and constant fraction discrimination. A comparison has also been made for the measured time resolutions with some of the other fast photomultipliers. (orig.)

Depth-of-interaction measurement in a single-layer crystal array with a single-ended readout using digital silicon photomultiplier

International Nuclear Information System (INIS)

Lee, Min Sun; Lee, Jae Sung

2015-01-01

We present the first experimental evaluation of a depth-of-interaction (DOI) positron emission tomography (PET) detector using a digital silicon photomultiplier (dSiPM). To measure DOI information from a mono-layer array of scintillation crystals with a single-ended readout, our group has previously proposed and developed a new method based on light spread using triangular reflectors. Since this method relies on measurement of the light distribution, dSiPM, which has a fully digital interface, has several merits for our DOI measurement. The DOI PET detector comprised of a dSiPM sensor (DPC-3200-22-44) coupled with a 14   ×   14 array of 2 mm  ×  2 mm  ×  20 mm unpolished LGSO crystals. All crystals were covered with triangular reflectors. To obtain a good performance of the DOI PET detector, several parameters of detector were selected as a preliminary experiment. Detector performance was evaluated with the selected parameters and the optimal experimental setup, and a DOI measurement was conducted by irradiating the crystal block at five DOI positions spaced at intervals of 4 mm. Maximum-likelihood estimation was employed for DOI positioning and the optimal DOI estimation scheme was also investigated in this study. As a result, the DOI PET detector showed clear crystal identification. The energy resolution (full-width at half-maximum (FWHM)) averaged over all depths was 10.21%  ±  0.15% at 511 keV, and time resolution averaged over all depths was 1198.61   ±   39.70 ps FWHM. The average DOI positioning accuracy for all depths was 74.22%  ±  6.77%, which equates to DOI resolution of 4.67 mm. Energy and DOI resolutions were uniform over all crystal positions except for the back parts of the array. Furthermore, additional simulation studies were conducted to verify the results of our DOI measurement method that is combined with dSiPM technology. In conclusion, our continuous DOI PET detector

Novel scintillators and silicon photomultipliers for nuclear physics and applications

International Nuclear Information System (INIS)

Jenkins, David

2015-01-01

Until comparatively recently, scintillator detectors were seen as an old-fashioned tool of nuclear physics with more attention being given to areas such as gamma-ray tracking using high-purity germanium detectors. Next-generation scintillator detectors, such as lanthanum bromide, which were developed for the demands of space science and gamma- ray telescopes, are found to have strong applicability to low energy nuclear physics. Their excellent timing resolution makes them very suitable for fast timing measurements and their much improved energy resolution compared to conventional scintillators promises to open up new avenues in nuclear physics research which were presently hard to access. Such 'medium-resolution' spectroscopy has broad interest across several areas of contemporary interest such as the study of nuclear giant resonances. In addition to the connections to space science, it is striking that the demands of contemporary medical imaging have strong overlap with those of experimental nuclear physics. An example is the interest in PET-MRI combined imaging which requires putting scintillator detectors in a high magnetic field environment. This has led to strong advances in the area of silicon photomultipliers, a solid-state replacement for photomultiplier tubes, which are insensitive to magnetic fields. Broad application to nuclear physics of this technology may be foreseen. (paper)

Four-channel surface coil array for sequential CW-EPR image acquisition

Science.gov (United States)

Enomoto, Ayano; Emoto, Miho; Fujii, Hirotada; Hirata, Hiroshi

2013-09-01

This article describes a four-channel surface coil array to increase the area of visualization for continuous-wave electron paramagnetic resonance (CW-EPR) imaging. A 776-MHz surface coil array was constructed with four independent surface coil resonators and three kinds of switches. Control circuits for switching the resonators were also built to sequentially perform EPR image acquisition for each resonator. The resonance frequencies of the resonators were shifted using PIN diode switches to decouple the inductively coupled coils. To investigate the area of visualization with the surface coil array, three-dimensional EPR imaging was performed using a glass cell phantom filled with a solution of nitroxyl radicals. The area of visualization obtained with the surface coil array was increased approximately 3.5-fold in comparison to that with a single surface coil resonator. Furthermore, to demonstrate the applicability of this surface coil array to animal imaging, three-dimensional EPR imaging was performed in a living mouse with an exogenously injected nitroxyl radical imaging agent.

Gain stabilization circuit of measuring devices with photomultipliers

International Nuclear Information System (INIS)

Seda, J.; Sabol, J.

1974-01-01

A circuit is designed for the stabilization of the gain of measuring devices with photomultipliers, suitable especially for the stabilization of scintillation detection systems, in which the correction signal is applied to the photomultiplier grid placed between the photocathode and the first dynode. (J.K.)

Transverse Oscillations for Phased Array Vector Velocity Imaging

DEFF Research Database (Denmark)

Pihl, Michael Johannes; Jensen, Jørgen Arendt

2010-01-01

of superficial blood vessels. To broaden the usability of the method, it should be expanded to a phased array geometry enabling vector velocity imaging of the heart. Therefore, the scan depth has to be increased to 10-15 cm. This paper presents suitable pulse echo fields (PEF). Two lines are beamformed...... (correlation coefficient, R: -0.76), and therefore predict estimator performance. CV is correlated with the standard deviation (R=0.74). The results demonstrate the potential for using a phased array for vector velocity imaging at larger depths, and potentially for imaging the heart....

Active terahertz imaging with Ne indicator lamp detector arrays

Science.gov (United States)

Kopeika, N. S.; Abramovich, A.; Yadid-Pecht, O.; Yitzhaky, Y.

2009-08-01

The advantages of terahertz (THz) imaging are well known. They penetrate well most non-conducting media and there are no known biological hazards, This makes such imaging systems important for homeland security, as they can be used to image concealed objects and often into rooms or buildings from the outside. There are also biomedical applications that are arising. Unfortunately, THz imaging is quite expensive, especially for real time systems, largely because of the price of the detector. Bolometers and pyroelectric detectors can each easily cost at least hundreds of dollars if not more, thus making focal plane arrays of them quite expensive. We have found that common miniature commercial neon indicator lamps costing typically about 30 cents each exhibit high sensitivity to THz radiation [1-3], with microsecond order rise times, thus making them excellent candidates for such focal plane arrays. NEP is on the order of 10-10 W/Hz1/2. Significant improvement of detection performance is expected when heterodyne detection is used Efforts are being made to develop focal plane array imagers using such devices at 300 GHz. Indeed, preliminary images using 4x4 arrays have already been obtained. An 8x8 VLSI board has been developed and is presently being tested. Since no similar imaging systems have been developed previously, there are many new problems to be solved with such a novel and unconventional imaging system. These devices act as square law detectors, with detected signal proportional to THz power. This allows them to act as mixers in heterodyne detection, thus allowing NEP to be reduced further by almost two orders of magnitude. Plans are to expand the arrays to larger sizes, and to employ super resolution techniques to improve image quality beyond that ordinarily obtainable at THz frequencies.

Application of position-sensitive detectors to positron imaging

International Nuclear Information System (INIS)

Yamashita, Takaji; Uchida, Hiroshi; Watanabe, Mitsuo; Omura, Tomohide

1994-01-01

Positron imaging including positron emission tomography (PET) is expected to be a promising tool for basic and clinical research, because it makes possible the study of regional chemistry within multiple organs of the body in living human beings and experimental animals. New schemes of high resolution block detectors have been developed to improve the performance of positron imaging systems, which employ small segments of bismuth germanate (BGO) arrays and position-sensitive photomultiplier tubes (PS-PMT). The coincidence detector resolution of less than 2.0 mm in full width at half maximum was achieved with the detectors, which is very close to the theoretical resolution limit in positron imaging. (author)

Sensitivity encoded silicon photomultiplier--a new sensor for high-resolution PET-MRI.

Science.gov (United States)

Schulz, Volkmar; Berker, Yannick; Berneking, Arne; Omidvari, Negar; Kiessling, Fabian; Gola, Alberto; Piemonte, Claudio

2013-07-21

Detectors for simultaneous positron emission tomography and magnetic resonance imaging in particular with sub-mm spatial resolution are commonly composed of scintillator crystal arrays, readout via arrays of solid state sensors, such as avalanche photo diodes (APDs) or silicon photomultipliers (SiPMs). Usually a light guide between the crystals and the sensor is used to enable the identification of crystals which are smaller than the sensor elements. However, this complicates crystal identification at the gaps and edges of the sensor arrays. A solution is to use as many sensors as crystals with a direct coupling, which unfortunately increases the complexity and power consumption of the readout electronics. Since 1997, position-sensitive APDs have been successfully used to identify sub-mm crystals. Unfortunately, these devices show a limitation in their time resolution and a degradation of spatial resolution when placed in higher magnetic fields. To overcome these limitations, this paper presents a new sensor concept that extends conventional SiPMs by adding position information via the spatial encoding of the channel sensitivity. The concept allows a direct coupling of high-resolution crystal arrays to the sensor with a reduced amount of readout channels. The theory of sensitivity encoding is detailed and linked to compressed sensing to compute unique sparse solutions. Two devices have been designed using one- and two-dimensional linear sensitivity encoding with eight and four readout channels, respectively. Flood histograms of both devices show the capability to precisely identify all 4 × 4 LYSO crystals with dimensions of 0.93 × 0.93 × 10 mm(3). For these crystals, the energy and time resolution (MV ± SD) of the devices with one (two)-dimensional encoding have been measured to be 12.3 · (1 ± 0.047)% (13.7 · (1 ± 0.047)%) around 511 keV with a paired coincidence time resolution (full width at half maximum) of 462 · (1 ± 0.054) ps (452 · (1 ± 0

A novel fast-neutron tomography system based on a plastic scintillator array and a compact D–D neutron generator

International Nuclear Information System (INIS)

Adams, Robert; Zboray, Robert; Prasser, Horst-Michael

2016-01-01

Very few experimental imaging studies using a compact neutron generator have been published, and to the knowledge of the authors none have included tomography results using multiple projection angles. Radiography results with a neutron generator, scintillator screen, and camera can be seen in Bogolubov et al. (2005), Cremer et al. (2012), and Li et al. (2014). Comparable results with a position-sensitive photomultiplier tube can be seen in Popov et al. (2011). One study using an array of individual fast neutron detectors in the context of cargo scanning for security purposes is detailed in Eberhardt et al. (2005). In that case, however, the emphasis was on very large objects with a resolution on the order of 1 cm, whereas this study focuses on less massive objects and a finer spatial resolution. In Andersson et al. (2014) three fast neutron counters and a D–T generator were used to perform attenuation measurements of test phantoms. Based on the axisymmetry of the test phantoms, the single-projection information was used to calculate radial attenuation distributions of the object, which was compared with the known geometry. In this paper a fast-neutron tomography system based on an array of individual detectors and a purpose-designed compact D–D neutron generator is presented. Each of the 88 detectors consists of a plastic scintillator read out by two Silicon photomultipliers and a dedicated pulse-processing board. Data acquisition for all channels was handled by four single-board microcontrollers. Details of the individual detector design and testing are elaborated upon. Using the complete array, several fast-neutron images of test phantoms were reconstructed, one of which was compared with results using a Co-60 gamma source. The system was shown to be capable of 2 mm resolution, with exposure times on the order of several hours per reconstructed tomogram. Details about these measurements and the analysis of the reconstructed images are given, along with a

Performances of multi-channel ceramic photomultipliers

International Nuclear Information System (INIS)

Comby, G.; Karolak, M.; Piret, Y.; Mouly, J.P.

1995-09-01

Ceramic electron multipliers with real metal dynodes and independent channels ware constructed using multilayer ceramic technology. Tests of these prototypes show their capability to form sensitive detectors such as photomultipliers or light intensifiers. Here, we present results for the photocathode sensitivity, dynode activation, gain, linearity range and dynamic characteristics as well as the effect of 3-year aging of the main operational functions. The advantages provided by the ceramic components are discussed. These results motivate the development of a compact 256 pixel ceramic photomultiplier. (author)

An overview of current developments in position-sensitive hybrid photon detectors and photo-multiplier tubes

CERN Document Server

Gys, Thierry

1999-01-01

Current developments in position-sensitive hybrid photon detectors and photo-multiplier tubes have stimulated increased interest from a variety of fields such as astronomy, biomedical imaging and high- energy physics. These devices are sensitive to single photons over a photon energy spectrum defined by the transmission of the optical entrance window and the photo-cathode type. Their spatial resolution ranges from a few millimeters for pad hybrid photon detectors and multi-anode photo-multiplier tubes down to a few tens of microns for pixel hybrid photon detectors and electron-bombarded charge-coupled devices. Basic technological and design aspects are assessed in this paper. (21 refs).

An innovative silicon photomultiplier digitizing camera for gamma-ray astronomy

Energy Technology Data Exchange (ETDEWEB)

Heller, M. [DPNC-Universite de Geneve, Geneva (Switzerland); Schioppa, E. Jr; Porcelli, A.; Pujadas, I.T.; Della Volpe, D.; Montaruli, T.; Cadoux, F.; Favre, Y.; Christov, A.; Rameez, M.; Miranda, L.D.M. [DPNC-Universite de Geneve, Geneva (Switzerland); Zietara, K.; Idzkowski, B.; Jamrozy, M.; Ostrowski, M.; Stawarz, L.; Zagdanski, A. [Jagellonian University, Astronomical Observatory, Krakow (Poland); Aguilar, J.A. [DPNC-Universite de Geneve, Geneva (Switzerland); Universite Libre Bruxelles, Faculte des Sciences, Brussels (Belgium); Prandini, E.; Lyard, E.; Neronov, A.; Walter, R. [Universite de Geneve, Department of Astronomy, Geneva (Switzerland); Rajda, P.; Bilnik, W.; Kasperek, J.; Lalik, K.; Wiecek, M. [AGH University of Science and Technology, Krakow (Poland); Blocki, J.; Mach, E.; Michalowski, J.; Niemiec, J.; Skowron, K.; Stodulski, M. [Instytut Fizyki Jadrowej im. H. Niewodniczanskiego Polskiej Akademii Nauk, Krakow (Poland); Bogacz, L. [Jagiellonian University, Department of Information Technologies, Krakow (Poland); Borkowski, J.; Frankowski, A.; Janiak, M.; Moderski, R. [Polish Academy of Science, Nicolaus Copernicus Astronomical Center, Warsaw (Poland); Bulik, T.; Grudzinska, M. [University of Warsaw, Astronomical Observatory, Warsaw (Poland); Mandat, D.; Pech, M.; Schovanek, P. [Institute of Physics of the Czech Academy of Sciences, Prague (Czech Republic); Marszalek, A.; Stodulska, M. [Instytut Fizyki Jadrowej im. H. Niewodniczanskiego Polskiej Akademii Nauk, Krakow (Poland); Jagellonian University, Astronomical Observatory, Krakow (Poland); Pasko, P.; Seweryn, K. [Centrum Badan Kosmicznych Polskiej Akademii Nauk, Warsaw (Poland); Sliusar, V. [Universite de Geneve, Department of Astronomy, Geneva (Switzerland); Taras Shevchenko National University of Kyiv, Astronomical Observatory, Kyiv (Ukraine)

2017-01-15

The single-mirror small-size telescope (SST-1M) is one of the three proposed designs for the small-size telescopes (SSTs) of the Cherenkov Telescope Array (CTA) project. The SST-1M will be equipped with a 4 m-diameter segmented reflector dish and an innovative fully digital camera based on silicon photo-multipliers. Since the SST sub-array will consist of up to 70 telescopes, the challenge is not only to build telescopes with excellent performance, but also to design them so that their components can be commissioned, assembled and tested by industry. In this paper we review the basic steps that led to the design concepts for the SST-1M camera and the ongoing realization of the first prototype, with focus on the innovative solutions adopted for the photodetector plane and the readout and trigger parts of the camera. In addition, we report on results of laboratory measurements on real scale elements that validate the camera design and show that it is capable of matching the CTA requirements of operating up to high moonlight background conditions. (orig.)

Stabilization of the photomultiplier gain of a liquid scintillation counter

International Nuclear Information System (INIS)

Alkhazov, I.D.; Dmitriev, V.D.; Kuznetsov, A.V.; Malkin, L.Z.; Petrov, B.F.; Sheremet'ev, A.K.; Shpakov, V.I.

1987-01-01

A stabilization system of photomultiplier gain, where light-emitting diode flashes have been used to obtain a reference signal, is described. The diode is placed just in the liquid scintilllator volume. The stabilization system contains several (according to the number of photomultipliers) identical channels, which of them consists of a colorimeter, a control trigger and an integrator with an operational amplifier. Increase of photomultiplier stability is reached by changing voltage of photomultiplier power according to the reference signal amplitude. The level of background and efficiency of neutron detection by a scintillation counter are unchanged when using the stabilization system for 10 days of measurements

A novel Silicon Photomultiplier with bulk integrated quench resistors: utilization in optical detection and tracking applications for particle physics

Energy Technology Data Exchange (ETDEWEB)

Petrovics, Stefan, E-mail: stp@hll.mpg.de [Halbleiterlabor der Max-Planck Gesellschaft, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Andricek, Ladislav [Halbleiterlabor der Max-Planck Gesellschaft, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Diehl, Inge; Hansen, Karsten [DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Jendrysik, Christian [Infineon Technologies AG, Am Campeon 1-12, D-85579 Neubiberg (Germany); Krueger, Katja [DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Lehmann, Raik; Ninkovic, Jelena [Halbleiterlabor der Max-Planck Gesellschaft, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Reckleben, Christian [DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Richter, Rainer; Schaller, Gerhard; Schopper, Florian [Halbleiterlabor der Max-Planck Gesellschaft, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Sefkow, Felix [DESY, Notkestrasse 85, D-22607 Hamburg (Germany)

2017-02-11

Silicon Photomultipliers (SiPMs) are a promising candidate for replacing conventional photomultiplier tubes (PMTs) in many applications, thanks to ongoing developments and advances in their technology. Conventional SiPMs are generally an array of avalanche photo diodes, operated in Geiger mode and read out in parallel, thus leading to the necessity of a high ohmic quenching resistor. This resistor enables passive quenching and is usually located on top of the array, limiting the fill factor of the device. In this paper, a novel detector concept with a bulk integrated quenching resistor will be recapped. In addition, due to other advantages of this novel detector design, a new concept, in which these devices will be utilized as tracking detectors for particle physics applications will be introduced, as well as first simulation studies and experimental measurements of this new approach. - Highlights: • A novel SiPM concept with bulk integrated quenching resistor is shown. • First prototypes of these SiPMs as tracking detectors are proposed. • Simulations of the Geiger efficiency suggest feasible operations at low overbias. • First measurements of the electron detection efficiency show promising results. • Measurements are in good agreement with the simulations.

Time resolution performance studies of contemporary high speed photomultipliers

International Nuclear Information System (INIS)

Leskovar, B.; Lo, C.C.

1978-01-01

The time resolution capabilities of prototype microchannel plate and static crossed-field photomultipliers have been investigated. Measurements were made of electron transit time, rise time, time response, single phtoelectron time spread and multiphotoelectron time spread for LEP HR350 proximity focused high gain curved microchannel plate and VPM-154A/1.6L static crossed-field photomultipliers. The experimental data have been compared with results obtained with conventionally designed high speed photomultipliers. Descriptions are given of both the measuring techniques and the measuring systems. 16 refs

Two-dimensional diced scintillator array for innovative, fine-resolution gamma camera

International Nuclear Information System (INIS)

Fujita, T.; Kataoka, J.; Nishiyama, T.; Ohsuka, S.; Nakamura, S.; Yamamoto, S.

2014-01-01

We are developing a technique to fabricate fine spatial resolution (FWHM<0.5mm) and cost-effective photon counting detectors, by using silicon photomultipliers (SiPMs) coupled with a finely pixelated scintillator plate. Unlike traditional X-ray imagers that use a micro-columnar CsI(Tl) plate, we can pixelate various scintillation crystal plates more than 1 mm thick, and easily develop large-area, fine-pitch scintillator arrays with high precision. Coupling a fine pitch scintillator array with a SiPM array results in a compact, fast-response detector that is ideal for X-ray, gamma-ray, and charged particle detection as used in autoradiography, gamma cameras, and photon counting CTs. As the first step, we fabricated a 2-D, cerium-doped Gd 3 Al 2 Ga 3 O 12 (Ce:GAGG) scintillator array of 0.25 mm pitch, by using a dicing saw to cut micro-grooves 50μm wide into a 1.0 mm thick Ce:GAGG plate. The scintillator plate is optically coupled with a 3.0×3.0mm pixel 4×4 SiPM array and read-out via the resistive charge-division network. Even when using this simple system as a gamma camera, we obtained excellent spatial resolution of 0.48 mm (FWHM) for 122 keV gamma-rays. We will present our plans to further improve the signal-to-noise ratio in the image, and also discuss a variety of possible applications in the near future

Pre-selecting muon events in the camera server of the ASTRI telescopes for the Cherenkov Telescope Array

Science.gov (United States)

Maccarone, Maria C.; Mineo, Teresa; Capalbi, Milvia; Conforti, Vito; Coffaro, Martina

2016-08-01

The Cherenkov Telescope Array (CTA) represents the next generation of ground based observatories for very high energy gamma ray astronomy. The CTA will consist of two arrays at two different sites, one in the northern and one in the southern hemisphere. The current CTA design foresees, in the southern site, the installation of many tens of imaging atmospheric Cherenkov telescopes of three different classes, namely large, medium, and small, so defined in relation to their mirror area; the northern hemisphere array would consist of few tens of the two larger telescope types. The telescopes will be equipped with cameras composed either of photomultipliers or silicon photomultipliers, and with different trigger and read-out electronics. In such a scenario, several different methods will be used for the telescopes' calibration. Nevertheless, the optical throughput of any CTA telescope, independently of its type, can be calibrated analyzing the characteristic image produced by local atmospheric highly energetic muons that induce the emission of Cherenkov light which is imaged as a ring onto the focal plane if their impact point is relatively close to the telescope optical axis. Large sized telescopes would be able to detect useful muon events under stereo coincidence and such stereo muon events will be directly addressed to the central CTA array data acquisition pipeline to be analyzed. For the medium and small sized telescopes, due to their smaller mirror area and large inter-telescope distance, the stereo coincidence rate will tend to zero; nevertheless, muon events will be detected by single telescopes that must therefore be able to identify them as possible useful calibration candidates, even if no stereo coincidence is available. This is the case for the ASTRI telescopes, proposed as pre-production units of the small size array of the CTA, which are able to detect muon events during regular data taking without requiring any dedicated trigger. We present two fast

Advances in gas avalanche photomultipliers

CERN Document Server

Breskin, Amos; Buzulutskov, A F; Chechik, R; Garty, E; Shefer, G; Singh, B K

2000-01-01

Gas avalanche detectors, combining solid photocathodes with fast electron multipliers, provide an attractive solution for photon localization over very large sensitive areas and under high illumination flux. They offer single-photon sensitivity and the possibility of operation under very intense magnetic fields. We discuss the principal factors governing the operation of gas avalanche photomultipliers. We summarize the recent progress made in alkali-halide and CVD-diamond UV-photocathodes, capable of operation under gas multiplication, and novel thin-film protected alkali-antimonide photocathodes, providing, for the first time, the possibility of operating gas photomultipliers in the visible range. Electron multipliers, adequate for these photon detectors, are proposed and some applications are briefly discussed.

Scintillation counter: photomultiplier tube alignment

International Nuclear Information System (INIS)

Olson, R.E.

1975-01-01

A scintillation counter, particularly for counting gamma ray photons, includes a massive lead radiation shield surrounding a sample-receiving zone. The shield is disassembleable into a plurality of segments to allow facile installation and removal of a photomultiplier tube assembly, the segments being so constructed as to prevent straight-line access of external radiation through the shield into the sample receiving zone. Provisions are made for accurately aligning the photomultiplier tube with respect to one or more sample-transmitting bores extending through the shield to the sample receiving zone. A sample elevator, used in transporting samples into the zone, is designed to provide a maximum gamma-receiving aspect to maximize the gamma detecting efficiency. (auth)

ATMAD: robust image analysis for Automatic Tissue MicroArray De-arraying.

Science.gov (United States)

Nguyen, Hoai Nam; Paveau, Vincent; Cauchois, Cyril; Kervrann, Charles

2018-04-19

Over the last two decades, an innovative technology called Tissue Microarray (TMA), which combines multi-tissue and DNA microarray concepts, has been widely used in the field of histology. It consists of a collection of several (up to 1000 or more) tissue samples that are assembled onto a single support - typically a glass slide - according to a design grid (array) layout, in order to allow multiplex analysis by treating numerous samples under identical and standardized conditions. However, during the TMA manufacturing process, the sample positions can be highly distorted from the design grid due to the imprecision when assembling tissue samples and the deformation of the embedding waxes. Consequently, these distortions may lead to severe errors of (histological) assay results when the sample identities are mismatched between the design and its manufactured output. The development of a robust method for de-arraying TMA, which localizes and matches TMA samples with their design grid, is therefore crucial to overcome the bottleneck of this prominent technology. In this paper, we propose an Automatic, fast and robust TMA De-arraying (ATMAD) approach dedicated to images acquired with brightfield and fluorescence microscopes (or scanners). First, tissue samples are localized in the large image by applying a locally adaptive thresholding on the isotropic wavelet transform of the input TMA image. To reduce false detections, a parametric shape model is considered for segmenting ellipse-shaped objects at each detected position. Segmented objects that do not meet the size and the roundness criteria are discarded from the list of tissue samples before being matched with the design grid. Sample matching is performed by estimating the TMA grid deformation under the thin-plate model. Finally, thanks to the estimated deformation, the true tissue samples that were preliminary rejected in the early image processing step are recognized by running a second segmentation step. We

Time resolution performance studies of contemporary high speed photomultipliers

International Nuclear Information System (INIS)

Leskovar, B.; Lo, C.C.

1977-01-01

The time resolution capabilities of prototype microchannel plate and static crossed-field photomultipliers have been investigated. Measurements were made of electron transit time, rise time, time response, single photoelectron time spread and multiphotoelectron time spread for LEP HR350 proximity focused high gain curved microchannel plate and VPM-154A/1.6L static crossed-field photomultipliers. The experimental data have been compared with results obtained with conventionally designed RCS 8850 and C31024 high speed photomultipliers. Descriptions are given of both the measuring techniques and the measuring systems

Future photomultiplier assemblies and associated electrons in large experiments

International Nuclear Information System (INIS)

Duteil, P.; Hammarstroem, R.; Innocenti, P.G.; Michelini, A.; Smith, B.; Soso, F.

1977-01-01

The results are presented of a working group study on reducing costs of proposed counter experiments in high-energy physics where several thousand photomultipliers are involved. Photomultiplier design is briefly discussed and new designs are presented for tube housings and high-voltage supplies. An outline presentation is given of a simplified electronics system, based on the Eurocard, for fast logic, data handling, and associated power supplies, suitable for photomultipliers or wire counters. Substantial savings in cost are shown to be possible without affecting performance but with some loss in convenience. (Auth.)

Noise in the Measurement of Light with Photomultipliers

Energy Technology Data Exchange (ETDEWEB)

Robben, F

1968-05-15

In order to be able to compare measurements derived from the anode current of a photomultiplier with measurement derived from photoelectron pulse counting, a systematic investigation of the properties of some photomultiplier tubes has been made. This has led to a correlation of the properties of a photomultiplier based on the quantum efficiency {eta}, the gain G, a photoelectron loss factor S and an effective dark rate D. In terms of these quantities the signal to noise ratio of an experimental measurement can be calculated, given the light flux and measurement technique. The fluctuations in a photomultiplier output are divided into two parts; Poisson fluctuations, and those due to excess noise. It is experimentally shown, from measurements on a 931A photomultiplier, that the excess noise exceeds the Poisson fluctuations only at very low frequencies, or long DC measurement times (> 10 s), for both pulse counting and anode current measurements. The Poisson fluctuations are found to be approximately the same for both pulse counting and anode current measurements, at both high light levels where the dark current, or dark pulses, are negligible, as well as at low light levels where the dark current is dominant. The excess noise is found to be somewhat greater in the case of anode current measurements. Thus both pulse counting and anode current measurement techniques have nearly identical noise properties, as far as the photomultiplier is concerned, and selection of either experimental technique depends primarily on the properties of the electronic equipment. By use of a synchronous detection technique, the variance of the pulse count was measured experimentally to an accuracy of {+-} 4 %, and was shown to be in agreement with that predicted by Poisson statistics.

The development of a high-resolution scintillating fiber tracker with silicon photomultiplier readout

International Nuclear Information System (INIS)

Roper Yearwood, Gregorio

2013-01-01

In this work I present the design and test results for a novel, modular tracking detector from scintillating fibers which are read out by silicon photomultiplier (SiPM) arrays. The detector modules consist of 0.25 mm thin scintillating fibers which are closely packed in five-layer ribbons. Two ribbons are fixed to both sides of a carbon-fiber composite structure. Custom made SiPM arrays with a photo-detection efficiency of about 50% read out the fibers. Several 860 mm long and 32 mm wide tracker modules were tested in a secondary 12 GeV/c beam at the PS facilities, CERN in November of 2009. During this test a spatial resolution better than 0.05 mm at an average light yield of about 20 photons for a minimum ionizing particle was determined. This work details the characterization of scintillating fibers and silicon photomultipliers of different make and model. It gives an overview of the production of scintillating fiber modules. The behavior of detector modules during the test-beam is analyzed in detail and different options for the front-end electronics are compared. Furthermore, the implementation of the proposed tracking detector from scintillating fibers within the scope of the PERDaix experiment is discussed. The PERDaix detector is a permanent magnet spectrometer with a weight of 40 kg. It consists of 8 tracking detector layers from scintillating fibers, a time-of-flight detector from plastic scintillator bars with silicon photomultiplier readout and a transition radiation detector from an irregular fleece radiator and Xe/CO 2 filled proportional counting tubes. The PERDaix detector was launched with a helium balloon within the scope of the ''Balloon-Experiments for University Students'' (BEXUS) program from Kiruna, Sweden in November 2010. For a few hours PERDaix reached an altitude of 33 km and measured cosmic rays. In May 2011, the PERDaix detector was characterized during a test-beam at the PS-facilities at CERN. This work introduces methods for event

ISPA (imaging silicon pixel array) experiment

CERN Document Server

Patrice Loïez

2002-01-01

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

Development of a spherically focused phased array transducer for ultrasonic image-guided hyperthermia

OpenAIRE

Liu, Jingfei; Foiret, Josquin; Stephens, Douglas N.; Le Baron, Olivier; Ferrara, Katherine W.

2016-01-01

A 1.5 MHz prolate spheroidal therapeutic array with 128 circular elements was designed to accommodate standard imaging arrays for ultrasonic image-guided hyperthermia. The implementation of this dual-array system integrates real-time therapeutic and imaging functions with a single ultrasound system (Vantage 256, Verasonics). To facilitate applications involving small animal imaging and therapy the array was designed to have a beam depth of field smaller than 3.5 mm and to electronically steer...

Digital image processing software system using an array processor

International Nuclear Information System (INIS)

Sherwood, R.J.; Portnoff, M.R.; Journeay, C.H.; Twogood, R.E.

1981-01-01

A versatile array processor-based system for general-purpose image processing was developed. At the heart of this system is an extensive, flexible software package that incorporates the array processor for effective interactive image processing. The software system is described in detail, and its application to a diverse set of applications at LLNL is briefly discussed. 4 figures, 1 table

Code-modulated interferometric imaging system using phased arrays

Science.gov (United States)

Chauhan, Vikas; Greene, Kevin; Floyd, Brian

2016-05-01

Millimeter-wave (mm-wave) imaging provides compelling capabilities for security screening, navigation, and bio- medical applications. Traditional scanned or focal-plane mm-wave imagers are bulky and costly. In contrast, phased-array hardware developed for mass-market wireless communications and automotive radar promise to be extremely low cost. In this work, we present techniques which can allow low-cost phased-array receivers to be reconfigured or re-purposed as interferometric imagers, removing the need for custom hardware and thereby reducing cost. Since traditional phased arrays power combine incoming signals prior to digitization, orthogonal code-modulation is applied to each incoming signal using phase shifters within each front-end and two-bit codes. These code-modulated signals can then be combined and processed coherently through a shared hardware path. Once digitized, visibility functions can be recovered through squaring and code-demultiplexing operations. Pro- vided that codes are selected such that the product of two orthogonal codes is a third unique and orthogonal code, it is possible to demultiplex complex visibility functions directly. As such, the proposed system modulates incoming signals but demodulates desired correlations. In this work, we present the operation of the system, a validation of its operation using behavioral models of a traditional phased array, and a benchmarking of the code-modulated interferometer against traditional interferometer and focal-plane arrays.

Sharpening spots: correcting for bleedover in cDNA array images.

Science.gov (United States)

Therneau, Terry; Tschumper, Renee C; Jelinek, Diane

2002-03-01

For cDNA array methods that depend on imaging of a radiolabel, we show that bleedover of one spot onto another, due to the gap between the array and the imaging media, can be a major problem. The images can be sharpened, however, using a blind convolution method based on the EM algorithm. The sharpened images look like a set of donuts, which concurs with our knowledge of the spotting process. Oversharpened images are actually useful as well, in locating the centers of each spot.

Rice8987 Array: Gel images - RMOS | LSDB Archive [Life Science Database Archive metadata

Lifescience Database Archive (English)

Full Text Available List Contact us RMOS Rice8987 Array: Gel images Data detail Data name Rice8987 Array: Gel images DOI 10.1890...e by Wako), was used to other Dplate. Gel images were scanned by scanner (Molecular Dynamics Co.). Number of...Database Site Policy | Contact Us Rice8987 Array: Gel images - RMOS | LSDB Archive ...

Linearity measurement of the XP 1210 fast photomultiplier tube

International Nuclear Information System (INIS)

Breuze, G.; Sawine, P.

1969-01-01

A new X Y method of photomultipliers linearity measurement has been tested which is more suitable for fast photomultiplier tubes. The XP 1210 gives a linearity limit of 70 mA for the gain 10, i.e. 3.5 V for a 50 Ω charge impedance

Selectable six-element multicoil array for entire spine imaging

International Nuclear Information System (INIS)

Byrne, J.W.; Bluma-Walter, J.; Prorok, R.J.

1990-01-01

This article introduces a new multicoil array that can provide entire spine imaging in two acquisitions with no need to manually reposition either the coil or the patient. A selectable contoured multicoil array with six elements was used to obtain coverage of the entire spine. The first four elements were used for imaging the upper spine region (cervical/thoracic) during the first acquisition, and the last four elements were used for imaging the lower spine region (thoracic/lumbar) during the second acquisition. The overall coil length was approximately 75 cm

Simultaneous molecular and anatomical imaging of the mouse in vivo

International Nuclear Information System (INIS)

Goertzen, Andrew L; Meadors, A Ken; Silverman, Robert W; Cherry, Simon R

2002-01-01

Non-invasive imaging technologies are opening up new windows into mouse biology. We have developed a mouse imaging system that integrates positron emission tomography (PET) with x-ray computed tomography (CT), allowing simultaneous anatomic and molecular imaging in vivo with the potential for precise registration of the two image volumes. The x-ray system consists of a compact mini-focal x-ray tube and an amorphous selenium flat panel x-ray detector with a low-noise CMOS readout. The PET system uses planar arrays of lutetium oxyorthosilicate scintillator coupled to position-sensitive photomultiplier tubes. We describe the design of this dual-modality imaging system and show, for the first time, simultaneously acquired PET and CT images in a phantom and in mice

Simultaneous molecular and anatomical imaging of the mouse in vivo

Energy Technology Data Exchange (ETDEWEB)

Goertzen, Andrew L [Crump Institute for Molecular Imaging, David Geffen School of Medicine at UCLA, Los Angeles, CA (United States); Meadors, A Ken [Crump Institute for Molecular Imaging, David Geffen School of Medicine at UCLA, Los Angeles, CA (United States); Silverman, Robert W [Crump Institute for Molecular Imaging, David Geffen School of Medicine at UCLA, Los Angeles, CA (United States); Cherry, Simon R [Department of Biomedical Engineering, University of California, Davis, Davis, CA (United States)

2002-12-21

Non-invasive imaging technologies are opening up new windows into mouse biology. We have developed a mouse imaging system that integrates positron emission tomography (PET) with x-ray computed tomography (CT), allowing simultaneous anatomic and molecular imaging in vivo with the potential for precise registration of the two image volumes. The x-ray system consists of a compact mini-focal x-ray tube and an amorphous selenium flat panel x-ray detector with a low-noise CMOS readout. The PET system uses planar arrays of lutetium oxyorthosilicate scintillator coupled to position-sensitive photomultiplier tubes. We describe the design of this dual-modality imaging system and show, for the first time, simultaneously acquired PET and CT images in a phantom and in mice.

Gigapixel imaging with microlens arrays

Science.gov (United States)

Orth, Antony; Schonbrun, Ethan

2016-03-01

A crucial part of the drug discovery process involves imaging the response of thousands of cell cultures to candidate drugs. Quantitative parameters from these "high content screens", such as protein expression and cell morphology, are extracted from fluorescence and brightfield micrographs. Due to the sheer number of cells that need to imaged for adequate statistics, the imaging time itself is a major bottleneck. Automated microscopes image small fields-of-view (FOVs) serially, which are then stitched together to form gigapixel-scale mosaics. We have developed a microscopy architecture that reduces mechanical overhead of traditional large field-of-view by parallelizing the image capture process. Instead of a single objective lens imaging FOVs one by one, we employ a microlens array for continuous photon capture, resulting in a 3-fold throughput increase. In this contribution, we present the design and imaging results of this microscopy architecture in three different contrast modes: multichannel fluorescence, hyperspectral fluorescence and brightfield.

Geneva University - Silicon photomultiplier : features and applications

CERN Multimedia

Université de Genève

2012-01-01

GENEVA UNIVERSITY École de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 Genève 4 Tél.: (022) 379 62 73 Fax: (022) 379 69 92   Wednesday 7 March 2012 SEMINAIRE DE PHYSIQUE CORPUSCULAIRE 11.15 a.m. - Science II, Auditoire 1S081, 30, quai Ernest-Ansermet, 1211 Genève 4 SILICON PHOTOMULTIPLIER : FEATURES AND APPLICATIONS Dr Giulio SARACINO   University of Naples, Federico II   Silicon photomultipliers were developed about ten years ago and their use, unlike traditional photomultiplier tubes, is increasing more and more. They are an evolution of the avalanche photodiode working in Geiger mode regime. Hundreds of such diodes are connected in parallel, allowing single photon response, high detection efficiency, high gain at low bias voltage and very good timing performance. In spite of their Geiger regime, they can be considered linear devices, until the number of photon...

Spatio-spectral color filter array design for optimal image recovery.

Science.gov (United States)

Hirakawa, Keigo; Wolfe, Patrick J

2008-10-01

In digital imaging applications, data are typically obtained via a spatial subsampling procedure implemented as a color filter array-a physical construction whereby only a single color value is measured at each pixel location. Owing to the growing ubiquity of color imaging and display devices, much recent work has focused on the implications of such arrays for subsequent digital processing, including in particular the canonical demosaicking task of reconstructing a full color image from spatially subsampled and incomplete color data acquired under a particular choice of array pattern. In contrast to the majority of the demosaicking literature, we consider here the problem of color filter array design and its implications for spatial reconstruction quality. We pose this problem formally as one of simultaneously maximizing the spectral radii of luminance and chrominance channels subject to perfect reconstruction, and-after proving sub-optimality of a wide class of existing array patterns-provide a constructive method for its solution that yields robust, new panchromatic designs implementable as subtractive colors. Empirical evaluations on multiple color image test sets support our theoretical results, and indicate the potential of these patterns to increase spatial resolution for fixed sensor size, and to contribute to improved reconstruction fidelity as well as significantly reduced hardware complexity.

Tests of crossed-wire position sensitive photomultipliers for scintillating fiber particle tracking

International Nuclear Information System (INIS)

Perdrisat, C.F.; Koechner, D.; Majewski, S.; Pourang, R.; Wilson, C.D.; Zorn, C.

1995-01-01

Several applications of two Hamamatsu position sensitive photomultiplier tubes to the detection of high energy particles with scintillating fibers are discussed. The PMTs are of the multiwire anode grid design, type R2486 and R4135. These tubes were tested with both single samples and arrays of 2 and 3 mm diameter scintillating fibers. Measurements of position resolution of the PMTs using either the charge digitization or the delay line readout techniques were made. The results indicate an intrinsic inability of the technique to reconstruct the actual position of a fiber on the photocathode when its location falls halfway between two grid wires. A way to overcome this limit is suggested. (orig.)

2D array design based on Fermat spiral for ultrasound imaging.

Science.gov (United States)

Martínez-Graullera, Oscar; Martín, Carlos J; Godoy, Gregorio; Ullate, Luis G

2010-02-01

The main challenge faced by 3D ultrasonic imaging with 2D array transducers is the large number of elements required to achieve an acceptable level of quality in the images. Therefore, the optimisation of the array layout, in order to reduce the number of active elements in the aperture, has been a research topic in the last years. Nowadays, array technology has made viable the production of 2D arrays with larger flexibility on elements size, shape and position, allowing to study other configurations different to the classical matrix organisation, such as circular, archimedes spiral or polygonal layout between others. In this work, the problem of designing an imaging system array with large apertures and a very limited number of active elements (N(e)=128 and N(e)=256) using the Fermat spiral layout has been studied. As summary, a general discussion about the most interesting cases is presented.

VUV-sensitive silicon-photomultipliers for the nEXO-experiment

Energy Technology Data Exchange (ETDEWEB)

Wrede, Gerrit; Bayerlein, Reimund; Hufschmidt, Patrick; Jamil, Ako; Schneider, Judith; Wagenpfeil, Michael; Ziegler, Tobias; Hoessl, Juergen; Anton, Gisela; Michel, Thilo [ECAP, Friedrich-Alexander-Universitaet Erlangen-Nuernberg (Germany)

2016-07-01

The nEXO (next Enriched Xenon Observatory) experiment will search for the neutrinoless double beta decay of Xe-136 with a liquid xenon TPC (Time ProjectionChamber). The sensitivity of the experiment is related to the energy resolution, which itself depends on the accuracies of the measurements of the amount of drifting electrons and the number of scintillation photons with their wavelength being in the vacuum ultraviolet band. Silicon Photomultipliers (SiPM) shall be used for the detection of the scintillation light, since they can be produced extremely radiopure. Commercially available SiPM do not fulfill all requirements of the nEXO experiment, thus a dedicated development is necessary. To characterize the silicon photomultipliers, we have built a test apparatus for xenon liquefaction, in which a VUV-sensitive photomultiplier tube can be operated together with the SiPM. In this contribution we present our apparatus for the SiPM characterization measurements and our latest results on the test of the silicon photomultipliers for the detection of xenon scintillation light.

Development of local oscillator integrated antenna array for microwave imaging diagnostics

International Nuclear Information System (INIS)

Kuwahara, D.; Shinohara, S.; Ito, N.; Nagayama, Y.; Tsuchiya, H.; Yoshikawa, M.; Kohagura, J.; Yoshinaga, T.; Yamaguchi, S.; Kogi, Y.; Mase, A.

2015-01-01

Microwave imaging diagnostics are powerful tools that are used to obtain details of complex structures and behaviors of such systems as magnetically confined plasmas. For example, microwave imaging reflectometry and microwave imaging interferometers are suitable for observing phenomena that are involved with electron density fluctuations; moreover, electron cyclotron emission imaging diagnostics enable us to accomplish the significant task of observing MHD instabilities in large tokamaks. However, microwave imaging systems include difficulties in terms of multi-channelization and cost. Recently, we solved these problems by developing a Horn-antenna Mixer Array (HMA), a 50 - 110 GHz 1-D heterodyne- type antenna array, which can be easily stacked as a 2-D receiving array, because it uses an end-fire element. However, the HMA still evidenced problems owing to the requirement for local oscillation (LO) optics and an expensive high-power LO source. To solve this problem, we have developed an upgraded HMA, named the Local Integrated Antenna array (LIA), in which each channel has an internal LO supply using a frequency multiplier integrated circuit. Therefore, the proposed antenna array eliminates the need for both the LO optics and the high-power LO source. This paper describes the principle of the LIA, and provides details about an 8 channel prototype LIA

Light Production in the Double Chooz Photomultiplier Tubes

Energy Technology Data Exchange (ETDEWEB)

Calvo, E.; Cerrada, M.; Crespo, J. I.; Gil-Botella, I.; Jimenez, S.; Lopez, M.; Novella, P.; Palomares, C.; Santorelli, R.; Verdugo, A.

2012-09-13

In this document we present a study of the phenomenon of light emission (called glowing) in the bases of the Hamamatsu R7081MOD-ASSY photomultiplier tubes (PMTs) used in the Double Chooz experiment. The tests have been carried out at the CIEMAT laboratories over a photomultiplier tube of the same model. We have studied the phenomenon making first a characterization of it, and then focusing on the dependence of the rate and the amount of emitted light versus voltage and temperature. In addition, we have looked for the possible existence of an ultraviolet component in the light which would be harmful for the experiment because it could be able to excite the scintillator liquid. Finally, we propose and test a method to reduce the light emission using a cover on the base of the photomultiplier tube.. (Author)

Clinical evaluation of phased array multicoil for spine MR imaging

International Nuclear Information System (INIS)

Miller, G.M.; Forbes, G.S.; Onofrio, B.M.; Rasmusson, J.J.

1990-01-01

Often, it is necessary to image the entire spinal canal or cord. Current surface coil technology necessitates a small field of view (FOV) and multiple coil placements, prolonging the examination. The Phased Array Multicoil (General Electric, Milwaukee, Wis) allows for high-resolution imaging of a larger segment of the spinal axis (48 cm), negating the need for multiple coil placements. The purpose of this paper is to determine whether, this technology can produce higher-quality images with equal or better expediency in a high-volume clinical practice. The studies were performed with a modified 1.5-T system (General Electric, Milwaukee, Wis). Multiple small surface coils are electronically linked so that each coil images only a small segment of the spinal column. The individual images are then fused to display one high-resolution 512-matrix image with up to a 48-cm FOV. A variety of four coil arrays were tested, including a 24-cm FOV dedicated cervical coil, 48-cm FOV shaped cervical/thoracic and straight thoracic/lumbar coils, and a six-coil array 75-cm entire spine coil. The images were then evaluated for overall quality, resolution, signal-to-noise ratio, and area of coverage

Primary gamma ray selection in a hybrid timing/imaging Cherenkov array

Directory of Open Access Journals (Sweden)

Postnikov E.B.

2017-01-01

Full Text Available This work is a methodical study on hybrid reconstruction techniques for hybrid imaging/timing Cherenkov observations. This type of hybrid array is to be realized at the gamma-observatory TAIGA intended for very high energy gamma-ray astronomy (> 30 TeV. It aims at combining the cost-effective timing-array technique with imaging telescopes. Hybrid operation of both of these techniques can lead to a relatively cheap way of development of a large area array. The joint approach of gamma event selection was investigated on both types of simulated data: the image parameters from the telescopes, and the shower parameters reconstructed from the timing array. The optimal set of imaging parameters and shower parameters to be combined is revealed. The cosmic ray background suppression factor depending on distance and energy is calculated. The optimal selection technique leads to cosmic ray background suppression of about 2 orders of magnitude on distances up to 450 m for energies greater than 50 TeV.

Image scanning microscopy using a SPAD detector array (Conference Presentation)

Science.gov (United States)

Castello, Marco; Tortarolo, Giorgio; Buttafava, Mauro; Tosi, Alberto; Sheppard, Colin J. R.; Diaspro, Alberto; Vicidomini, Giuseppe

2017-02-01

The use of an array of detectors can help overcoming the traditional limitation of confocal microscopy: the compromise between signal and theoretical resolution. Each element independently records a view of the sample and the final image can be reconstructed by pixel reassignment or by inverse filtering (e.g. deconvolution). In this work, we used a SPAD array of 25 detectors specifically designed for this goal and our scanning microscopy control system (Carma) to acquire the partial images and to perform online image processing. Further work will be devoted to optimize the image reconstruction step and to improve the fill-factor of the detector.

Mercuric iodide room-temperature array detectors for gamma-ray imaging

Energy Technology Data Exchange (ETDEWEB)

Patt, B. [Xsirius, Inc, Camarillo, CA (United States)

1994-11-15

Significant progress has been made recently in the development of mercuric iodide detector arrays for gamma-ray imaging, making real the possibility of constructing high-performance small, light-weight, portable gamma-ray imaging systems. New techniques have been applied in detector fabrication and then low noise electronics which have produced pixel arrays with high-energy resolution, high spatial resolution, high gamma stopping efficiency. Measurements of the energy resolution capability have been made on a 19-element protypical array. Pixel energy resolutions of 2.98% fwhm and 3.88% fwhm were obtained at 59 keV (241-Am) and 140-keV (99m-Tc), respectively. The pixel spectra for a 14-element section of the data is shown together with the composition of the overlapped individual pixel spectra. These techniques are now being applied to fabricate much larger arrays with thousands of pixels. Extension of these principles to imaging scenarios involving gamma-ray energies up to several hundred keV is also possible. This would enable imaging of the 208 keV and 375-414 keV 239-Pu and 240-Pu structures, as well as the 186 keV line of 235-U.

Fast photoacoustic imaging system based on 320-element linear transducer array

International Nuclear Information System (INIS)

Yin Bangzheng; Xing Da; Wang Yi; Zeng Yaguang; Tan Yi; Chen Qun

2004-01-01

A fast photoacoustic (PA) imaging system, based on a 320-transducer linear array, was developed and tested on a tissue phantom. To reconstruct a test tomographic image, 64 time-domain PA signals were acquired from a tissue phantom with embedded light-absorption targets. A signal acquisition was accomplished by utilizing 11 phase-controlled sub-arrays, each consisting of four transducers. The results show that the system can rapidly map the optical absorption of a tissue phantom and effectively detect the embedded light-absorbing target. By utilizing the multi-element linear transducer array and phase-controlled imaging algorithm, we thus can acquire PA tomography more efficiently, compared to other existing technology and algorithms. The methodology and equipment thus provide a rapid and reliable approach to PA imaging that may have potential applications in noninvasive imaging and clinic diagnosis

BI-ground microstrip array coil vs. conventional microstrip array coil for mouse imaging at 7 tesla

Science.gov (United States)

Hernández, Ricardo; Terrones, M. A. López; Jakob, P. M.

2012-10-01

At high field strengths, the need for more efficient high frequency coils has grown. Since the radiation losses and the interaction between coil and sample increase proportionally to field strength, the quality factor (Q) and the sensitivity of the coil decrease as consequence of these negative effects. Since Zhang et al proposed in 2001 a new surface coil based on the microstrip transmission line for high frequency, different Tx-Rx phased arrays based on this concept have been already introduced in animal and whole body systems at high field strengths, each of them with different modifications in order to get better field homogeneity, SNR or isolation between coil elements in the array. All these arrays for animals systems have been built for rat imaging. One of these modifications is called BI-Ground Microstrip Array Coil (BIGMAC). The implementation of a smaller two-channel BIGMAC design for mouse imaging is studied and its performance compared to a two-channel conventional Microstrip array at 7 Tesla, the higher isolation by using BIGMAC elements in comparison with conventional Microstrip elements is shown in this work.

Externally mounted radioactivity detector for MWD employing radial inline scintillator and photomultiplier tube

International Nuclear Information System (INIS)

Meisner, J.E.; Mumby, E.S.; Groeschel, V.E.

1991-01-01

Improved radioactivity well logging may be achieved by mounting a scintillator and photomultiplier tube in a single case interfacing with a hole extending through a drill collar at the lower end of a drill string so that measurements can be made while drilling. Radioactive sources (when required for well logging) are mounted in cavities which open to the exterior of the drill collar. Light from the scintillator is coupled directly to the aligned photomultiplier tube both of which are mounted in a case extending radially within the drill collar and sealingly engaging an electronics housing within the drill collar and the drill collar wall surrounding the hole. The scintillator is of greater diameter than the photomultiplier tube. A frustoconical light pipe connects the scintillator and the photomultiplier tube, channeling scintillation in the crystal to the photomultiplier to provide an amplified detection capability over that for a scintillator having the same diameter as the photomultiplier tube. (author)

Modeling the low-light response of photomultiplier tubes

Science.gov (United States)

Maxwell, Patrick; Niculescu, Ioana

2017-09-01

A number of crucial experiments exploring the intricate tomography of protons and neutrons will be carried out in Hall A at Jefferson Lab using the SuperBigBite Spectrometer (SBS), a large acceptance magnetic spectrometer sporting 0.5% momentum and 0.5 mr angular resolution. As part of the standard SBS detector package the Gas Ring Imaging Cherenkov (GRINCH) detector will help identify particles produced in the experiments. To determine which photomultiplier (PMT) tubes would be used in GRINCH, more than 900 29 mm 9125B PMTs were tested. Two models, were used to fit test data. For the parameters relevant to this study, results from both models were found to be equivalent, and will be discussed here.

Two-Slotted Surface Coil Array for Magnetic Resonance Imaging at 4 Tesla

International Nuclear Information System (INIS)

Solis, S. E.; Hernandez, J. A.; Rodriguez, A. O.; Tomasi, D.

2008-01-01

Arrays of antennas have been widely accepted for magnetic resonance imaging applications due to their high signal-to-noise ratio (SNR) over large volumes of interest. A new surface coil based on the magnetron tube and called slotted surface coil, has been recently introduced by our group. This coil design experimentally demonstrated a significant improvement over the circular-shaped coil when used in the receive-only mode. The slotted coils formed a two-sheet structure with a 90 deg. separation and each coil had 6 circular slots. Numerical simulations were performed using the finite element method for this coil design to study the behaviour of the array magnetic field. Then, we developed a two-coil array for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. In vitro images showed the feasibility of this coil array for standard pulses for high field magnetic resonance imaging

A BaF2 crystal array for high energy -ray measurements

Indian Academy of Sciences (India)

A very well-known such array is called two-arm-photon- spectrometer (TAPS) [1]. It consists of large (25 cm long) hexagonal BaF¾ crystals ar- ranged in packs of 64 crystals. ... light which may not reach the photomultiplier tube. A sketch of the ...

The Advanced Gamma-ray Imaging System (AGIS): Topological Array Trigger

Science.gov (United States)

Smith, Andrew W.

2010-03-01

AGIS is a concept for the next-generation ground-based gamma-ray observatory. It will be an array of 36 imaging atmospheric Cherenkov telescopes (IACTs) sensitive in the energy range from 50 GeV to 200 TeV. The required improvements in sensitivity, angular resolution, and reliability of operation relative to the present generation instruments imposes demanding technological and cost requirements on the design of the telescopes and on the triggering and readout systems for AGIS. To maximize the capabilities of large arrays of IACTs with a low energy threshold, a wide field of view and a low background rate, a sophisticated array trigger is required. We outline the status of the development of a stereoscopic array trigger that calculates image parameters and correlates them across a subset of telescopes. Field Programmable Gate Arrays (FPGAs) implement the real-time pattern recognition to suppress cosmic rays and night-sky background events. A proof of principle system is being developed to run at camera trigger rates up to 10MHz and array-level rates up to 10kHz.

Studies of a Next-Generation Silicon-Photomultiplier-Based Time-of-Flight PET/CT System.

Science.gov (United States)

Hsu, David F C; Ilan, Ezgi; Peterson, William T; Uribe, Jorge; Lubberink, Mark; Levin, Craig S

2017-09-01

This article presents system performance studies for the Discovery MI PET/CT system, a new time-of-flight system based on silicon photomultipliers. System performance and clinical imaging were compared between this next-generation system and other commercially available PET/CT and PET/MR systems, as well as between different reconstruction algorithms. Methods: Spatial resolution, sensitivity, noise-equivalent counting rate, scatter fraction, counting rate accuracy, and image quality were characterized with the National Electrical Manufacturers Association NU-2 2012 standards. Energy resolution and coincidence time resolution were measured. Tests were conducted independently on two Discovery MI scanners installed at Stanford University and Uppsala University, and the results were averaged. Back-to-back patient scans were also performed between the Discovery MI, Discovery 690 PET/CT, and SIGNA PET/MR systems. Clinical images were reconstructed using both ordered-subset expectation maximization and Q.Clear (block-sequential regularized expectation maximization with point-spread function modeling) and were examined qualitatively. Results: The averaged full widths at half maximum (FWHMs) of the radial/tangential/axial spatial resolution reconstructed with filtered backprojection at 1, 10, and 20 cm from the system center were, respectively, 4.10/4.19/4.48 mm, 5.47/4.49/6.01 mm, and 7.53/4.90/6.10 mm. The averaged sensitivity was 13.7 cps/kBq at the center of the field of view. The averaged peak noise-equivalent counting rate was 193.4 kcps at 21.9 kBq/mL, with a scatter fraction of 40.6%. The averaged contrast recovery coefficients for the image-quality phantom were 53.7, 64.0, 73.1, 82.7, 86.8, and 90.7 for the 10-, 13-, 17-, 22-, 28-, and 37-mm-diameter spheres, respectively. The average photopeak energy resolution was 9.40% FWHM, and the average coincidence time resolution was 375.4 ps FWHM. Clinical image comparisons between the PET/CT systems demonstrated the high

High-resolution imaging using a wideband MIMO radar system with two distributed arrays.

Science.gov (United States)

Wang, Dang-wei; Ma, Xiao-yan; Chen, A-Lei; Su, Yi

2010-05-01

Imaging a fast maneuvering target has been an active research area in past decades. Usually, an array antenna with multiple elements is implemented to avoid the motion compensations involved in the inverse synthetic aperture radar (ISAR) imaging. Nevertheless, there is a price dilemma due to the high level of hardware complexity compared to complex algorithm implemented in the ISAR imaging system with only one antenna. In this paper, a wideband multiple-input multiple-output (MIMO) radar system with two distributed arrays is proposed to reduce the hardware complexity of the system. Furthermore, the system model, the equivalent array production method and the imaging procedure are presented. As compared with the classical real aperture radar (RAR) imaging system, there is a very important contribution in our method that the lower hardware complexity can be involved in the imaging system since many additive virtual array elements can be obtained. Numerical simulations are provided for testing our system and imaging method.

Application of CMOS Technology to Silicon Photomultiplier Sensors

Science.gov (United States)

D’Ascenzo, Nicola; Zhang, Xi; Xie, Qingguo

2017-01-01

We use the 180 nm GLOBALFOUNDRIES (GF) BCDLite CMOS process for the production of a silicon photomultiplier prototype. We study the main characteristics of the developed sensor in comparison with commercial SiPMs obtained in custom technologies and other SiPMs developed with CMOS-compatible processes. We support our discussion with a transient modeling of the detection process of the silicon photomultiplier as well as with a series of static and dynamic experimental measurements in dark and illuminated environments. PMID:28946675

Fast-neutron and gamma-ray imaging with a capillary liquid xenon converter coupled to a gaseous photomultiplier

Science.gov (United States)

Israelashvili, I.; Coimbra, A. E. C.; Vartsky, D.; Arazi, L.; Shchemelinin, S.; Caspi, E. N.; Breskin, A.

2017-09-01

Gamma-ray and fast-neutron imaging was performed with a novel liquid xenon (LXe) scintillation detector read out by a Gaseous Photomultiplier (GPM). The 100 mm diameter detector prototype comprised a capillary-filled LXe converter/scintillator, coupled to a triple-THGEM imaging-GPM, with its first electrode coated by a CsI UV-photocathode, operated in Ne/5%CH4 at cryogenic temperatures. Radiation localization in 2D was derived from scintillation-induced photoelectron avalanches, measured on the GPM's segmented anode. The localization properties of 60Co gamma-rays and a mixed fast-neutron/gamma-ray field from an AmBe neutron source were derived from irradiation of a Pb edge absorber. Spatial resolutions of 12± 2 mm and 10± 2 mm (FWHM) were reached with 60Co and AmBe sources, respectively. The experimental results are in good agreement with GEANT4 simulations. The calculated ultimate expected resolutions for our application-relevant 4.4 and 15.1 MeV gamma-rays and 1-15 MeV neutrons are 2-4 mm and ~ 2 mm (FWHM), respectively. These results indicate the potential applicability of the new detector concept to Fast-Neutron Resonance Radiography (FNRR) and Dual-Discrete-Energy Gamma Radiography (DDEGR) of large objects.

A novel fast-neutron tomography system based on a plastic scintillator array and a compact D-D neutron generator.

Science.gov (United States)

Adams, Robert; Zboray, Robert; Prasser, Horst-Michael

2016-01-01

Very few experimental imaging studies using a compact neutron generator have been published, and to the knowledge of the authors none have included tomography results using multiple projection angles. Radiography results with a neutron generator, scintillator screen, and camera can be seen in Bogolubov et al. (2005), Cremer et al. (2012), and Li et al. (2014). Comparable results with a position-sensitive photomultiplier tube can be seen in Popov et al. (2011). One study using an array of individual fast neutron detectors in the context of cargo scanning for security purposes is detailed in Eberhardt et al. (2005). In that case, however, the emphasis was on very large objects with a resolution on the order of 1cm, whereas this study focuses on less massive objects and a finer spatial resolution. In Andersson et al. (2014) three fast neutron counters and a D-T generator were used to perform attenuation measurements of test phantoms. Based on the axisymmetry of the test phantoms, the single-projection information was used to calculate radial attenuation distributions of the object, which was compared with the known geometry. In this paper a fast-neutron tomography system based on an array of individual detectors and a purpose-designed compact D-D neutron generator is presented. Each of the 88 detectors consists of a plastic scintillator read out by two Silicon photomultipliers and a dedicated pulse-processing board. Data acquisition for all channels was handled by four single-board microcontrollers. Details of the individual detector design and testing are elaborated upon. Using the complete array, several fast-neutron images of test phantoms were reconstructed, one of which was compared with results using a Co-60 gamma source. The system was shown to be capable of 2mm resolution, with exposure times on the order of several hours per reconstructed tomogram. Details about these measurements and the analysis of the reconstructed images are given, along with a discussion

Contact CMOS imaging of gaseous oxygen sensor array.

Science.gov (United States)

Daivasagaya, Daisy S; Yao, Lei; Yi Yung, Ka; Hajj-Hassan, Mohamad; Cheung, Maurice C; Chodavarapu, Vamsy P; Bright, Frank V

2011-10-01

We describe a compact luminescent gaseous oxygen (O 2 ) sensor microsystem based on the direct integration of sensor elements with a polymeric optical filter and placed on a low power complementary metal-oxide semiconductor (CMOS) imager integrated circuit (IC). The sensor operates on the measurement of excited-state emission intensity of O 2 -sensitive luminophore molecules tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) ([Ru(dpp) 3 ] 2+ ) encapsulated within sol-gel derived xerogel thin films. The polymeric optical filter is made with polydimethylsiloxane (PDMS) that is mixed with a dye (Sudan-II). The PDMS membrane surface is molded to incorporate arrays of trapezoidal microstructures that serve to focus the optical sensor signals on to the imager pixels. The molded PDMS membrane is then attached with the PDMS color filter. The xerogel sensor arrays are contact printed on top of the PDMS trapezoidal lens-like microstructures. The CMOS imager uses a 32 × 32 (1024 elements) array of active pixel sensors and each pixel includes a high-gain phototransistor to convert the detected optical signals into electrical currents. Correlated double sampling circuit, pixel address, digital control and signal integration circuits are also implemented on-chip. The CMOS imager data is read out as a serial coded signal. The CMOS imager consumes a static power of 320 µW and an average dynamic power of 625 µW when operating at 100 Hz sampling frequency and 1.8 V DC. This CMOS sensor system provides a useful platform for the development of miniaturized optical chemical gas sensors.

Study of large hemispherical photomultiplier tubes for the ANTARES neutrino telescope

Science.gov (United States)

Aguilar, J. A.; Albert, A.; Ameli, F.; Amram, P.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardellier-Desages, F. E.; Aslanides, E.; Aubert, J.-J.; Bailey, D.; Basa, S.; Battaglieri, M.; Becherini, Y.; Bellotti, R.; Beltramelli, J.; Bertin, V.; Billault, M.; Blaes, R.; Blanc, F.; de Botton, N.; Boulesteix, J.; Bouwhuis, M. C.; Brooks, C. B.; Bradbury, S. M.; Bruijn, R.; Brunner, J.; Burgio, G. F.; Cafagna, F.; Calzas, A.; Capone, A.; Caponetto, L.; Carmona, E.; Carr, J.; Cartwright, S. L.; Castorina, E.; Cavasinni, V.; Cecchini, S.; Charvis, P.; Circella, M.; Colnard, C.; Compère, C.; Coniglione, R.; Cooper, S.; Coyle, P.; Cuneo, S.; Damy, G.; van Dantzig, R.; Deschamps, A.; de Marzo, C.; Denans, D.; Destelle, J.-J.; de Vita, R.; Dinkelspiler, B.; Distefano, C.; Drogou, J.-F.; Druillole, F.; Engelen, J.; Ernenwein, J.-P.; Falchini, E.; Favard, S.; Feinstein, F.; Ferry, S.; Festy, D.; Flaminio, V.; Fopma, J.; Fuda, J.-L.; Gallone, J.-M.; Giacomelli, G.; Girard, N.; Goret, P.; Graf, K.; Hallewell, G.; Hartmann, B.; Heijboer, A.; Hello, Y.; Hernández-Rey, J. J.; Herrouin, G.; Hößl, J.; Hoffmann, C.; Hubbard, J. R.; Jaquet, M.; de Jong, M.; Jouvenot, F.; Kappes, A.; Karg, T.; Karkar, S.; Karolak, M.; Katz, U.; Keller, P.; Kooijman, P.; Korolkova, E. V.; Kouchner, A.; Kretschmer, W.; Kuch, S.; Kudryavtsev, V. A.; Lafoux, H.; Lagier, P.; Lahmann, R.; Lamare, P.; Languillat, J.-C.; Laschinsky, H.; Laubier, L.; Legou, T.; Le Guen, Y.; Le Provost, H.; Le van Suu, A.; Lo Nigro, L.; Lo Presti, D.; Loucatos, S.; Louis, F.; Lyashuk, V.; Marcelin, M.; Margiotta, A.; Maron, C.; Massol, A.; Masullo, R.; Mazéas, F.; Mazure, A.; McMillan, J. E.; Migneco, E.; Millot, C.; Milovanovic, A.; Montanet, F.; Montaruli, T.; Morel, J.-P.; Morganti, M.; Moscoso, L.; Musumeci, M.; Naumann, C.; Naumann-Godo, M.; Nezri, E.; Niess, V.; Nooren, G. J.; Ogden, P.; Olivetto, C.; Palanque-Delabrouille, N.; Papaleo, R.; Payre, P.; Petta, C.; Piattelli, P.; Pineau, J.-P.; Poinsignon, J.; Popa, V.; Potheau, R.; Pradier, T.; Racca, C.; Raia, G.; Randazzo, N.; Real, D.; van Rens, B. A. P.; Réthoré, F.; Riccobene, G.; Rigaud, V.; Ripani, M.; Roca-Blay, V.; Rolin, J.-F.; Romita, M.; Rose, H. J.; Rostovtsev, A.; Ruppi, M.; Russo, G. V.; Sacquin, Y.; Salesa, F.; Salomon, K.; Saouter, S.; Sapienza, P.; Shanidze, R.; Schuller, J.-P.; Schuster, W.; Sokalski, I.; Spurio, M.; Stolarczyk, T.; Stubert, D.; Taiuti, M.; Thompson, L. F.; Tilav, S.; Valdy, P.; Valente, V.; Vallage, B.; Vernin, P.; Virieux, J.; de Vries, G.; de Witt Huberts, P.; de Wolf, E.; Zaborov, D.; Zaccone, H.; Zakharov, V.; Zornoza, J. D.; Zúñiga, J.

2005-12-01

The ANTARES neutrino telescope, to be immersed depth in the Mediterranean Sea, will consist of a three-dimensional matrix of 900 large area photomultiplier tubes housed in pressure-resistant glass spheres. The selection of the optimal photomultiplier was a critical step for the project and required an intensive phase of tests and developments carried out in close collaboration with the main manufacturers worldwide. This paper provides an overview of the tests performed by the collaboration and describes in detail the features of the photomultiplier tube chosen for ANTARES.

A double photomultiplier Compton camera and its readout system for mice imaging

Energy Technology Data Exchange (ETDEWEB)

Fontana, Cristiano Lino [Physics Department Galileo Galilei, University of Padua, Via Marzolo 8, Padova 35131 (Italy) and INFN Padova, Via Marzolo 8, Padova 35131 (Italy); Atroshchenko, Kostiantyn [Physics Department Galileo Galilei, University of Padua, Via Marzolo 8, Padova 35131 (Italy) and INFN Legnaro, Viale dell' Universita 2, Legnaro PD 35020 (Italy); Baldazzi, Giuseppe [Physics Department, University of Bologna, Viale Berti Pichat 6/2, Bologna 40127, Italy and INFN Bologna, Viale Berti Pichat 6/2, Bologna 40127 (Italy); Bello, Michele [INFN Legnaro, Viale dell' Universita 2, Legnaro PD 35020 (Italy); Uzunov, Nikolay [Department of Natural Sciences, Shumen University, 115 Universitetska str., Shumen 9712, Bulgaria and INFN Legnaro, Viale dell' Universita 2, Legnaro PD 35020 (Italy); Di Domenico, Giovanni [Physics Department, University of Ferrara, Via Saragat 1, Ferrara 44122 (Italy) and INFN Ferrara, Via Saragat 1, Ferrara 44122 (Italy)

2013-04-19

We have designed a Compton Camera (CC) to image the bio-distribution of gamma-emitting radiopharmaceuticals in mice. A CC employs the 'electronic collimation', i.e. a technique that traces the gamma-rays instead of selecting them with physical lead or tungsten collimators. To perform such a task, a CC measures the parameters of the Compton interaction that occurs in the device itself. At least two detectors are required: one (tracker), where the primary gamma undergoes a Compton interaction and a second one (calorimeter), in which the scattered gamma is completely absorbed. Eventually the polar angle and hence a 'cone' of possible incident directions are obtained (event with 'incomplete geometry'). Different solutions for the two detectors are proposed in the literature: our design foresees two similar Position Sensitive Photomultipliers (PMT, Hamamatsu H8500). Each PMT has 64 output channels that are reduced to 4 using a charge multiplexed readout system, i.e. a Series Charge Multiplexing net of resistors. Triggering of the system is provided by the coincidence of fast signals extracted at the last dynode of the PMTs. Assets are the low cost and the simplicity of design and operation, having just one type of device; among drawbacks there is a lower resolution with respect to more sophisticated trackers and full 64 channels Readout. This paper does compare our design of our two-Hamamatsu CC to other solutions and shows how the spatial and energy accuracy is suitable for the inspection of radioactivity in mice.

A study of timing properties of Silicon Photomultipliers

Science.gov (United States)

Avella, Paola; De Santo, Antonella; Lohstroh, Annika; Sajjad, Muhammad T.; Sellin, Paul J.

2012-12-01

Silicon Photomultipliers (SiPMs) are solid-state pixelated photodetectors. Lately these sensors have been investigated for Time of Flight Positron Emission Tomography (ToF-PET) applications, where very good coincidence time resolution of the order of hundreds of picoseconds imply spatial resolution of the order of cm in the image reconstruction. The very fast rise time typical of the avalanche discharge improves the time resolution, but can be limited by the readout electronics and the technology used to construct the device. In this work the parameters of the equivalent circuit of the device that directly affect the pulse shape, namely the quenching resistance and capacitance and the diode and parasitic capacitances, were calculated. The mean rise time obtained with different preamplifiers was also measured.

Study of a high gain microchannel plate photomultiplier having low statistical gain fluctuations

International Nuclear Information System (INIS)

Audier, M.

1980-12-01

A new photomultiplier configuration which synthesizes the performances of several models is proposed. The principles of microchannel plate photomultipliers are reviewed. The physical phenomena which limit the electron multiplication process in a microchannel and the detection efficiency of the microchannel plates are investigated. The operation of a herring-bone pattern device and of a system of two microchannel plate photomultipliers are described and characterized [fr

3-D Imaging using Row--Column-Addressed 2-D Arrays with a Diverging Lens

DEFF Research Database (Denmark)

Bouzari, Hamed; Engholm, Mathias; Stuart, Matthias Bo

2016-01-01

It has been shown that row–column-addressed (RCA) 2-D arrays can be an inexpensive alternative to fully addressed 2-D arrays. Generally imaging with an RCA 2-D array is limited to its forward-looking volume region. Constructing a double-curved RCA 2-D array or applying a diverging lens over......, is designed for imaging down to 14 cm at a volume rate of 88 Hz. The curvilinear imaging performance of a λ/2-pitch 3 MHz 62+62 RCA 2-D array is investigated as a function of depth, using a diverging lens with f-number of -1. The results of this study demonstrate that the proposed beamforming approach...

Time-Domain Fluorescence Lifetime Imaging Techniques Suitable for Solid-State Imaging Sensor Arrays

Directory of Open Access Journals (Sweden)

Robert K. Henderson

2012-05-01

Full Text Available We have successfully demonstrated video-rate CMOS single-photon avalanche diode (SPAD-based cameras for fluorescence lifetime imaging microscopy (FLIM by applying innovative FLIM algorithms. We also review and compare several time-domain techniques and solid-state FLIM systems, and adapt the proposed algorithms for massive CMOS SPAD-based arrays and hardware implementations. The theoretical error equations are derived and their performances are demonstrated on the data obtained from 0.13 μm CMOS SPAD arrays and the multiple-decay data obtained from scanning PMT systems. In vivo two photon fluorescence lifetime imaging data of FITC-albumin labeled vasculature of a P22 rat carcinosarcoma (BD9 rat window chamber are used to test how different algorithms perform on bi-decay data. The proposed techniques are capable of producing lifetime images with enough contrast.

The Advanced Gamma-ray Imaging System (AGIS): Real Time Stereoscopic Array Trigger

Science.gov (United States)

Byrum, K.; Anderson, J.; Buckley, J.; Cundiff, T.; Dawson, J.; Drake, G.; Duke, C.; Haberichter, B.; Krawzcynski, H.; Krennrich, F.; Madhavan, A.; Schroedter, M.; Smith, A.

2009-05-01

Future large arrays of Imaging Atmospheric Cherenkov telescopes (IACTs) such as AGIS and CTA are conceived to comprise of 50 - 100 individual telescopes each having a camera with 10**3 to 10**4 pixels. To maximize the capabilities of such IACT arrays with a low energy threshold, a wide field of view and a low background rate, a sophisticated array trigger is required. We describe the design of a stereoscopic array trigger that calculates image parameters and then correlates them across a subset of telescopes. Fast Field Programmable Gate Array technology allows to use lookup tables at the array trigger level to form a real-time pattern recognition trigger tht capitalizes on the multiple view points of the shower at different shower core distances. A proof of principle system is currently under construction. It is based on 400 MHz FPGAs and the goal is for camera trigger rates of up to 10 MHz and a tunable cosmic-ray background suppression at the array level.

Planetary Radar Imaging with the Deep-Space Network's 34 Meter Uplink Array

Science.gov (United States)

Vilnrotter, Victor; Tsao, P.; Lee, D.; Cornish, T.; Jao, J.; Slade, M.

2011-01-01

A coherent Uplink Array consisting of two or three 34-meter antennas of NASA's Deep Space Network has been developed for the primary purpose of increasing EIRP at the spacecraft. Greater EIRP ensures greater reach, higher uplink data rates for command and configuration control, as well as improved search and recovery capabilities during spacecraft emergencies. It has been conjectured that Doppler-delay radar imaging of lunar targets can be extended to planetary imaging, where the long baseline of the uplink array can provide greater resolution than a single antenna, as well as potentially higher EIRP. However, due to the well known R4 loss in radar links, imaging of distant planets is a very challenging endeavor, requiring accurate phasing of the Uplink Array antennas, cryogenically cooled low-noise receiver amplifiers, and sophisticated processing of the received data to extract the weak echoes characteristic of planetary radar. This article describes experiments currently under way to image the planets Mercury and Venus, highlights improvements in equipment and techniques, and presents planetary images obtained to date with two 34 meter antennas configured as a coherently phased Uplink Array.

Development of horn antenna mixer array with internal local oscillator module for microwave imaging diagnostics

Energy Technology Data Exchange (ETDEWEB)

Kuwahara, D., E-mail: dkuwahar@cc.tuat.ac.jp [Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Ito, N. [Department of Intelligent System Engineering, Ube National College of Technology, Ube, Yamaguchi 755-8555 (Japan); Nagayama, Y. [Department of Helical Plasma Research, National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Yoshinaga, T. [Department of Applied Physics, National Defense Academy, Yokosuka, Kanagawa 239-0811 (Japan); Yamaguchi, S. [Department of Pure and Applied Physics, Kansai University, Suita, Osaka 564-8680 (Japan); Yoshikawa, M.; Kohagura, J. [Graduate School of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Sugito, S. [Equipment Development Center, Institute for Molecular Science, Okazaki, Aichi 444-8585 (Japan); Kogi, Y. [Department of Information Electronics, Fukuoka Institute of Technology, Fukuoka, Fukuoka 811-0295 (Japan); Mase, A. [Art, Science and Technology Center for Cooperative Research, Kyusyu University, Kasuga, Fukuoka 816-8580 (Japan)

2014-11-15

A new antenna array is proposed in order to improve the sensitivity and complexity of microwave imaging diagnostics systems such as a microwave imaging reflectometry, a microwave imaging interferometer, and an electron cyclotron emission imaging. The antenna array consists of five elements: a horn antenna, a waveguide-to-microstrip line transition, a mixer, a local oscillation (LO) module, and an intermediate frequency amplifier. By using an LO module, the LO optics can be removed, and the supplied LO power to each element can be equalized. We report details of the antenna array and characteristics of a prototype antenna array.

Fabrication of prototype imaging arrays for SCUBA-2

International Nuclear Information System (INIS)

Hilton, G.C.; Beall, J.A.; Doriese, W.B.; Duncan, W.D.; Ferreira, L.S.; Irwin, K.D.; Reintsema, C.D.; Ullom, J.N.; Vale, L.R.; Xu, Y.; Zink, B.L.; Parkes, W.; Bunting, A.S.; Dunare, C.C.; Gundlach, A.M.; Stevenson, J.T.M.; Walton, A.J.; Schulte, E.; Corrales, E.; Sienicki, J.P.; Bintley, Dan; Ade, P.A.R.; Sudiwala, Rashmi V.; Woodcraft, Adam L.; Halpern, Mark; Holland, W.; Audley, M.D.; MacIntosh, M.

2006-01-01

Prototype imaging subarrays for SCUBA-2 (the Submillimeter Common-User Bolometer Array) have been fabricated and tested. The pixel count (1280) of these wafer-scale imagers is significantly larger than any other low-temperature detectors produced to date, and represents a major step forward for the low-temperature detector community. These transition-edge-sensor (TES) based imagers utilize several innovations including in-focal-plane superconducting quantum intereference device (SQUID) multiplexers, micromachined Si block absorbers, and superconducting wafer hybridization. In this paper, we review the fabrication processes developed for these imagers and present recent optical data from a prototype imaging subarray

Characterization and optimization of Silicon Photomultipliers and small size scintillator tiles for future calorimeter applications

CERN Document Server

AUTHOR|(CDS)2095312; Horváth, Ákos

For the active layers of highly granular sampling calorimeters, small scintillator tiles read out by Silicon Photomultipliers (SiPM) can be an interesting and cost effective alternative to silicon sensors. At CERN a test setup was realized for the development of new generations of calorimeters to characterize new types of Silicon Photomultipliers in terms of gain, noise, afterpulses and crosstalk and to study the impact of scintillator wrappings and the tile size on the measured light yield and uniformity. In this thesis work, the experimental setup is described and the steps for commissioning the equipment are discussed. Then, the temperature dependence of the Silicon Photomultiplier response will be investigated, including the dependence of bare Silicon Photomultipliers as well as Silicon Photomultipliers coupled to scintillator tiles. Finally, the tile-photomultiplier response for different tile sizes and coating options will be evaluated. The experimental setup will be extended to allow for the characteri...

The use of the multiple-gradient array for geoelectrical resistivity and induced polarization imaging

Science.gov (United States)

Aizebeokhai, Ahzegbobor P.; Oyeyemi, Kehinde D.

2014-12-01

The use of most conventional electrode configurations in electrical resistivity survey is often time consuming and labour intensive, especially when using manual data acquisition systems. Often, data acquisition teams tend to reduce data density so as to speed up field operation thereby reducing the survey cost; but this could significantly degrade the quality and resolution of the inverse models. In the present work, the potential of using the multiple-gradient array, a non-conventional electrode configuration, for practical cost effective and rapid subsurface resistivity and induced polarization mapping was evaluated. The array was used to conduct 2D resistivity and time-domain induced polarization imaging along two traverses in a study site at Ota, southwestern Nigeria. The subsurface was characterised and the main aquifer delineated using the inverse resistivity and chargeability images obtained. The performance of the multiple-gradient array was evaluated by correlating the 2D resistivity and chargeability images with those of the conventional Wenner array as well as the result of some soundings conducted along the same traverses using Schlumberger array. The multiple-gradient array has been found to have the advantage of measurement logistics and improved image resolution over the Wenner array.

Photomultiplier characteristics considerations for the deep underwater muon and neutrino detection system

International Nuclear Information System (INIS)

Leskovar, B.

1980-01-01

The results of an investigation of the characteristics of photomultipliers for the Deep Underwater Muon and Neutrino Detection (DUMAND) System are discussed. The pulse-height resolution, the afterpulsing phenomena and the gain sensitivity to the ambient magnetic field have been determined for large photocathode area photomultipliers. Furthermore, the transient time difference, the single photoelectron time spread, and the collection and photocathode quantum efficiency uniformity as a function of the position of the photocathode sensing area have been reviewed. Finally, an attempt has been made to estimate the photomultiplier reliability and its lifetime

Far-infrared imaging arrays for fusion plasma density and magnetic field measurements

International Nuclear Information System (INIS)

Neikirk, D.P.; Rutledge, D.B.

1982-01-01

Far-infrared imaging detector arrays are required for the determination of density and local magnetic field in fusion plasmas. Analytic calculations point out the difficulties with simple printed slot and dipole antennas on ungrounded substrates for use in submillimeter wave imaging arrays because of trapped surface waves. This is followed by a discussion of the use of substrate-lens coupling to eliminate the associated trapped surface modes responsible for their poor performance. This integrates well with a modified bow-tie antenna and permits diffraction-limited imaging. Arrays using bismuth microbolometers have been successfully fabricated and tested at 1222μm and 119μm. A 100 channel pilot experiment designed for the UCLA Microtor tokamak is described. (author)

Performance of 8- and 12-dynode stage multianode photo-multipliers

Energy Technology Data Exchange (ETDEWEB)

Bibby, J.H. [University of Oxford, Oxford (United Kingdom); Buckley, A. [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom); Chamonal, R.J.U. [University of Edinburgh, Edinburgh (United Kingdom)]. E-mail: chamonal@ph.ed.ac.uk; Easo, S. [CCLRC, Rutherford Aplleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom); Eisenhardt, S. [University of Edinburgh, Edinburgh (United Kingdom); Gibson, V. [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom); Harnew, N. [University of Oxford, Oxford (United Kingdom); Muheim, F. [University of Edinburgh, Edinburgh (United Kingdom); Howard, A. [Imperial College, London (United Kingdom); Lawrence, J. [University of Edinburgh, Edinburgh (United Kingdom); Pickford, A. [University of Glasgow, Glasgow (United Kingdom); Plackett, R. [Imperial College, London (United Kingdom); Price, D.R. [Imperial College, London (United Kingdom); Rademacker, J. [University of Oxford, Oxford (United Kingdom); Smale, N. [University of Oxford, Oxford (United Kingdom); Soler, F.J.P. [University of Glasgow, Glasgow (United Kingdom); CCLRC, Rutherford Aplleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom); Somerville, L. [University of Oxford, Oxford (United Kingdom); Storey, J. [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom); Websdale, D. [Imperial College, London (United Kingdom); Wotton, S. [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom)

2006-11-01

We report on studies of 64-channel Multianode Photo-Multiplier Tubes (MaPMTs) as photo-detectors for Ring Imaging CHerenkov (RICH) counters. The newly available 8-dynode stage MaPMT was tested in particle beams at CERN. The MaPMT signals were read out directly with the Beetle1.2 chip which was designed for the LHCb environment and operates at 40MHz. The photon yield and signal losses were determined for a cluster of 3x3 close-packed MaPMTs. The performance of the 8-dynode stage MaPMT was compared to that of the 12-dynode stage MaPMT which has a larger intrinsic gain.

Ontology-based, Tissue MicroArray oriented, image centered tissue bank

Directory of Open Access Journals (Sweden)

Viti Federica

2008-04-01

Full Text Available Abstract Background Tissue MicroArray technique is becoming increasingly important in pathology for the validation of experimental data from transcriptomic analysis. This approach produces many images which need to be properly managed, if possible with an infrastructure able to support tissue sharing between institutes. Moreover, the available frameworks oriented to Tissue MicroArray provide good storage for clinical patient, sample treatment and block construction information, but their utility is limited by the lack of data integration with biomolecular information. Results In this work we propose a Tissue MicroArray web oriented system to support researchers in managing bio-samples and, through the use of ontologies, enables tissue sharing aimed at the design of Tissue MicroArray experiments and results evaluation. Indeed, our system provides ontological description both for pre-analysis tissue images and for post-process analysis image results, which is crucial for information exchange. Moreover, working on well-defined terms it is then possible to query web resources for literature articles to integrate both pathology and bioinformatics data. Conclusions Using this system, users associate an ontology-based description to each image uploaded into the database and also integrate results with the ontological description of biosequences identified in every tissue. Moreover, it is possible to integrate the ontological description provided by the user with a full compliant gene ontology definition, enabling statistical studies about correlation between the analyzed pathology and the most commonly related biological processes.

Three-dimensional real-time synthetic aperture imaging using a rotating phased array transducer

DEFF Research Database (Denmark)

Nikolov, Svetoslav; Dufait, Remi; Schoisswohl, Armin

2002-01-01

phased array, which is rotated over the volume of interest. The data is acquired using coded signals and synthetic transmit aperture imaging. Only one group of elements transmits at a time. The delays are set such as to form a cylindrical wave. The back-scattered signal carries information not only from......Current 3D real-time imaging is done either with sparse 2D arrays, or with mechanically moved phased arrays. The former results in a poor resolution and contrast due to a limited amount of elements. The latter has the disadvantage of low frame rates due to the sequential acquisition of the volume...... line-by-line and plane-by-plane. This paper describes an approach which combines mechanically moved phased array with synthetic transmit aperture imaging, resulting in high volume acquisition rates without a trade-off in image quality. The scan method uses a conventional fully populated 64 element...

Silicon photomultipliers in scintillation detectors used for gamma ray energies up to 6.1 MeV

Science.gov (United States)

Grodzicka-Kobylka, M.; Szczesniak, T.; Moszyński, M.; Swiderski, L.; Szawłowski, M.

2017-12-01

Majority of papers concerning scintillation detectors with light readout by means of silicon photomultipliers refer to nuclear medicine or radiation monitoring devices where energy of detected gamma rays do not exceed 2 MeV. Detection of gamma radiation with higher energies is of interest to e.g. high energy physics and plasma diagnostics. The aim of this paper is to study applicability (usefulness) of SiPM light readout in detection of gamma rays up to 6.1 MeV in combination with various scintillators. The reported measurements were made with 3 samples of one type of Hamamatsu TSV (Through-Silicon Via technology) MPPC arrays. These 4x4 channel arrays have a 50 × 50 μm2 cell size and 12 × 12 mm2 effective active area. The following scintillators were used: CeBr3, NaI:Tl, CsI:Tl. During all the tests detectors were located in a climatic chamber. The studies are focused on optimization of the MPPC performance for practical use in detection of high energy gamma rays. The optimization includes selection of the optimum operating voltage in respect to the required energy resolution, dynamic range, linearity and pulse amplitude. The presented temperature tests show breakdown voltage dependence on the temperature change and define requirements for a power supply and gain stabilization method. The energy spectra for energies between 511 keV and 6.1 MeV are also presented and compared with data acquired with a classic photomultiplier XP5212B readout. Such a comparison allowed study of nonlinearity of the tested MPPCs, correction of the energy spectra and proper analysis of the energy resolution.

Cherenkov TOF PET with silicon photomultipliers

Science.gov (United States)

Dolenec, R.; Korpar, S.; Križan, P.; Pestotnik, R.

2015-12-01

As previously demonstrated, an excellent timing resolution below 100 ps FWHM is possible in time-of-flight positron emission tomography (TOF PET) if the detection method is based on the principle of detecting photons of Cherenkov light, produced in a suitable material and detected by microchannel plate photomultipliers (MCP PMTs). In this work, the silicon photomultipliers (SiPMs) were tested for the first time as the photodetectors in Cherenkov TOF PET. The high photon detection efficiency (PDE) of SiPMs led to a large improvement in detection efficiency. On the other hand, the time response of currently available SiPMs is not as good as that of MCP PMTs. The SiPM dark counts introduce a new source of random coincidences in Cherenkov method, which would be overwhelming with present SiPM technology at room temperature. When the apparatus was cooled, its performance significantly improved.

Rectangle Surface Coil Array in a Grid Arrangement for Resonance Imaging

Science.gov (United States)

2016-02-13

magnet wires with insulating coating for rectangular surface coils. The wires are formed into four one turn 145mm x 32mm rectangular coils...switchable array, RF magnetic field, NQR, MRI, NMR, tuning, decoupling I. INTRODUCTION ESONANCE imaging can be accomplished using Nuclear Magnetic ...grid array. This achieves the switchable array configuration. Later, investigations will have circuit controlled multiplexer for switching to

Research on geometric rectification of the Large FOV Linear Array Whiskbroom Image

Science.gov (United States)

Liu, Dia; Liu, Hui-tong; Dong, Hao; Liu, Xiao-bo

2015-08-01

To solve the geometric distortion problem of large FOV linear array whiskbroom image, a model of multi center central projection collinearity equation was founded considering its whiskbroom and linear CCD imaging feature, and the principle of distortion was analyzed. Based on the rectification method with POS, we introduced the angular position sensor data of the servo system, and restored the geometric imaging process exactly. An indirect rectification scheme aiming at linear array imaging with best scanline searching method was adopted, matrixes for calculating the exterior orientation elements was redesigned. We improved two iterative algorithms for this device, and did comparison and analysis. The rectification for the images of airborne imaging experiment showed ideal effect.

NeuroSeek dual-color image processing infrared focal plane array

Science.gov (United States)

McCarley, Paul L.; Massie, Mark A.; Baxter, Christopher R.; Huynh, Buu L.

1998-09-01

Several technologies have been developed in recent years to advance the state of the art of IR sensor systems including dual color affordable focal planes, on-focal plane array biologically inspired image and signal processing techniques and spectral sensing techniques. Pacific Advanced Technology (PAT) and the Air Force Research Lab Munitions Directorate have developed a system which incorporates the best of these capabilities into a single device. The 'NeuroSeek' device integrates these technologies into an IR focal plane array (FPA) which combines multicolor Midwave IR/Longwave IR radiometric response with on-focal plane 'smart' neuromorphic analog image processing. The readout and processing integrated circuit very large scale integration chip which was developed under this effort will be hybridized to a dual color detector array to produce the NeuroSeek FPA, which will have the capability to fuse multiple pixel-based sensor inputs directly on the focal plane. Great advantages are afforded by application of massively parallel processing algorithms to image data in the analog domain; the high speed and low power consumption of this device mimic operations performed in the human retina.

Non-descanned multifocal multiphoton microscopy with a multianode photomultiplier tube

International Nuclear Information System (INIS)

Cha, Jae Won; Yew, Elijah Y. S.; Kim, Daekeun; Subramanian, Jaichandar; Nedivi, Elly; So, Peter T. C.

2015-01-01

Multifocal multiphoton microscopy (MMM) improves imaging speed over a point scanning approach by parallelizing the excitation process. Early versions of MMM relied on imaging detectors to record emission signals from multiple foci simultaneously. For many turbid biological specimens, the scattering of emission photons results in blurred images and degrades the signal-to-noise ratio (SNR). We have recently demonstrated that a multianode photomultiplier tube (MAPMT) placed in a descanned configuration can effectively collect scattered emission photons from each focus into their corresponding anodes significantly improving image SNR for highly scattering specimens. Unfortunately, a descanned MMM has a longer detection path resulting in substantial emission photon loss. Optical design constraints in a descanned geometry further results in significant optical aberrations especially for large field-of-view (FOV), high NA objectives. Here, we introduce a non-descanned MMM based on MAPMT that substantially overcomes most of these drawbacks. We show that we improve signal efficiency up to fourfold with limited image SNR degradation due to scattered emission photons. The excitation foci can also be spaced wider to cover the full FOV of the objective with minimal aberrations. The performance of this system is demonstrated by imaging interneuron morphological structures deep in the brains of living mice

Non-descanned multifocal multiphoton microscopy with a multianode photomultiplier tube

Energy Technology Data Exchange (ETDEWEB)

Cha, Jae Won; Yew, Elijah Y. S. [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA (United States); Kim, Daekeun [Department of Mechanical Engineering, Dankook University (Korea, Republic of); Subramanian, Jaichandar [Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA (United States); Nedivi, Elly [Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA (United States); Departments of Brain and Cognitive Sciences, and Biology, Massachusetts Institute of Technology, Cambridge, MA (United States); So, Peter T. C. [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA (United States); Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA (United States)

2015-08-15

Multifocal multiphoton microscopy (MMM) improves imaging speed over a point scanning approach by parallelizing the excitation process. Early versions of MMM relied on imaging detectors to record emission signals from multiple foci simultaneously. For many turbid biological specimens, the scattering of emission photons results in blurred images and degrades the signal-to-noise ratio (SNR). We have recently demonstrated that a multianode photomultiplier tube (MAPMT) placed in a descanned configuration can effectively collect scattered emission photons from each focus into their corresponding anodes significantly improving image SNR for highly scattering specimens. Unfortunately, a descanned MMM has a longer detection path resulting in substantial emission photon loss. Optical design constraints in a descanned geometry further results in significant optical aberrations especially for large field-of-view (FOV), high NA objectives. Here, we introduce a non-descanned MMM based on MAPMT that substantially overcomes most of these drawbacks. We show that we improve signal efficiency up to fourfold with limited image SNR degradation due to scattered emission photons. The excitation foci can also be spaced wider to cover the full FOV of the objective with minimal aberrations. The performance of this system is demonstrated by imaging interneuron morphological structures deep in the brains of living mice.

Silicon Photomultipliers (SiPM) as novel photodetectors for PET

International Nuclear Information System (INIS)

Del Guerra, Alberto; Belcari, Nicola; Giuseppina Bisogni, Maria; Corsi, Francesco; Foresta, Maurizio; Guerra, Pedro; Marcatili, Sara; Santos, Andres; Sportelli, Giancarlo

2011-01-01

Next generation PET scanners should fulfill very high requirements in terms of spatial, energy and timing resolution. Modern scanner performances are inherently limited by the use of standard photomultiplier tubes. The use of Silicon Photomultipliers (SiPMs) is proposed for the construction of a 4D-PET module of 4.8x4.8 cm 2 aimed to replace the standard PMT based PET block detector. The module will be based on a LYSO continuous crystal read on two faces by Silicon Photomultipliers. A high granularity detection surface made by SiPM matrices of 1.5 mm pitch will be used for the x-y photon hit position determination with submillimetric accuracy, while a low granularity surface constituted by 16 mm 2 SiPM pixels will provide the fast timing information (t) that will be used to implement the Time of Flight technique (TOF). The spatial information collected by the two detector layers will be combined in order to measure the Depth of Interaction (DOI) of each event (z). The use of large area multi-pixel Silicon Photomultiplier (SiPM) detectors requires the development of a multichannel Data Acquisition system (DAQ) as well as of a dedicated front-end in order not to degrade the intrinsic detector capabilities and to manage many channels. The paper describes the progress made on the development of the proof of principle module under construction at the University of Pisa.

Arrays of Segmented, Tapered Light Guides for Use With Large, Planar Scintillation Detectors

Science.gov (United States)

Raylman, Raymond R.; Vaigneur, Keith; Stolin, Alexander V.; Jaliparthi, Gangadhar

2015-06-01

Metabolic imaging techniques can potentially improve detection and diagnosis of cancer in women with radiodense and/or fibrocystic breasts. Our group has previously developed a high-resolution positron emission tomography imaging and biopsy device (PEM-PET) to detect and guide the biopsy of suspicious breast lesions. Initial testing revealed that the imaging field-of-view (FOV) of the scanner was smaller than the physical size of the detector's active area, which could hinder sampling of breast areas close to the chest wall. The purpose of this work was to utilize segmented, tapered light guides for optically coupling the scintillator arrays to arrays of position-sensitive photomultipliers to increase both the active FOV and identification of individual scintillator elements. Testing of the new system revealed that the optics of these structures made it possible to discern detector elements from the complete active area of the detector face. In the previous system the top and bottom rows and left and right columns were not identifiable. Additionally, use of the new light guides increased the contrast of individual detector elements by up to 129%. Improved element identification led to a spatial resolution increase by approximately 12%. Due to attenuation of light in the light guides the detector energy resolution decreased from 18.5% to 19.1%. Overall, these improvements should increase the field-of-view and spatial resolution of the dedicated breast-PET system.

Fabrication, characterization and testing of silicon photomultipliers for the Muon Portal Project

International Nuclear Information System (INIS)

La Rocca, P.; Billotta, S.; Blancato, A.A.; Bonanno, D.; Bonanno, G.; Fallica, G.; Garozzo, S.; Lo Presti, D.; Marano, D.; Pugliatti, C.; Riggi, F.; Romeo, G.; Santagati, G.; Valvo, G.

2015-01-01

The Muon Portal is a recently started Project aiming at the construction of a large area tracking detector that exploits the muon tomography technique to inspect the contents of traveling cargo containers. The detection planes will be made of plastic scintillator strips with embedded wavelength-shifting fibres. Special designed silicon photomultipliers will read the scintillation light transported by the fibres along the strips and a dedicated electronics will combine signals from different strips to reduce the overall number of channels, without loss of information. Different silicon photomultiplier prototypes, both with the p-on-n and n-on-p technologies, have been produced by STMicroelectronics during the last years. In this paper we present the main characteristics of the silicon photomultipliers designed for the Muon Portal Project and describe the setup and the procedure implemented for the characterization of these devices, giving some statistical results obtained from the test of a first batch of silicon photomultipliers

Fabrication, characterization and testing of silicon photomultipliers for the Muon Portal Project

Energy Technology Data Exchange (ETDEWEB)

La Rocca, P., E-mail: paola.larocca@ct.infn.it [Dipartimento di Fisica e Astronomia - Catania (Italy); INFN - Sezione di Catania (Italy); Billotta, S. [INAF - Osservatorio Astrofisico di Catania (Italy); Blancato, A.A.; Bonanno, D. [Dipartimento di Fisica e Astronomia - Catania (Italy); Bonanno, G. [INAF - Osservatorio Astrofisico di Catania (Italy); Fallica, G. [STMicroelectronics - Catania (Italy); Garozzo, S. [INAF - Osservatorio Astrofisico di Catania (Italy); Lo Presti, D. [Dipartimento di Fisica e Astronomia - Catania (Italy); INFN - Sezione di Catania (Italy); Marano, D. [INAF - Osservatorio Astrofisico di Catania (Italy); Pugliatti, C.; Riggi, F. [Dipartimento di Fisica e Astronomia - Catania (Italy); INFN - Sezione di Catania (Italy); Romeo, G. [INAF - Osservatorio Astrofisico di Catania (Italy); Santagati, G. [Dipartimento di Fisica e Astronomia - Catania (Italy); INFN - Sezione di Catania (Italy); Valvo, G. [STMicroelectronics - Catania (Italy)

2015-07-01

The Muon Portal is a recently started Project aiming at the construction of a large area tracking detector that exploits the muon tomography technique to inspect the contents of traveling cargo containers. The detection planes will be made of plastic scintillator strips with embedded wavelength-shifting fibres. Special designed silicon photomultipliers will read the scintillation light transported by the fibres along the strips and a dedicated electronics will combine signals from different strips to reduce the overall number of channels, without loss of information. Different silicon photomultiplier prototypes, both with the p-on-n and n-on-p technologies, have been produced by STMicroelectronics during the last years. In this paper we present the main characteristics of the silicon photomultipliers designed for the Muon Portal Project and describe the setup and the procedure implemented for the characterization of these devices, giving some statistical results obtained from the test of a first batch of silicon photomultipliers.

Highly-Integrated CMOS Interface Circuits for SiPM-Based PET Imaging Systems.

Science.gov (United States)

Dey, Samrat; Lewellen, Thomas K; Miyaoka, Robert S; Rudell, Jacques C

2012-01-01

Recent developments in the area of Positron Emission Tomography (PET) detectors using Silicon Photomultipliers (SiPMs) have demonstrated the feasibility of higher resolution PET scanners due to a significant reduction in the detector form factor. The increased detector density requires a proportionally larger number of channels to interface the SiPM array with the backend digital signal processing necessary for eventual image reconstruction. This work presents a CMOS ASIC design for signal reducing readout electronics in support of an 8×8 silicon photomultiplier array. The row/column/diagonal summation circuit significantly reduces the number of required channels, reducing the cost of subsequent digitizing electronics. Current amplifiers are used with a single input from each SiPM cathode. This approach helps to reduce the detector loading, while generating all the necessary row, column and diagonal addressing information. In addition, the single current amplifier used in our Pulse-Positioning architecture facilitates the extraction of pulse timing information. Other components under design at present include a current-mode comparator which enables threshold detection for dark noise current reduction, a transimpedance amplifier and a variable output impedance I/O driver which adapts to a wide range of loading conditions between the ASIC and lines with the off-chip Analog-to-Digital Converters (ADCs).

Reconstruction of quasimonochromatic images for multispectral x-ray imaging with a pinhole array and a flat Bragg mirror

International Nuclear Information System (INIS)

Izumi, N.; Barbee, T. W.; Koch, J. A.; Mancini, R. C.; Welser, L. A.

2006-01-01

We have developed a software package for reconstruction of quasimonochromatic images from a multiple monochromatic x-ray imager for inertial confinement fusion implosions. The instrument consists of a pinhole array, a multilayer Bragg mirror, and an image detector. The pinhole array projects hundreds of images onto the detector after reflection off the multilayer Bragg mirror, which introduces spectral dispersion along the reflection axis. The quasimonochromatic images of line emissions and continuum emissions can be used for measurement of temperature and density maps of implosion plasmas. In this article, we describe a computer-aided processing technique for systematic reconstruction of quasimonochromatic images from raw data. This technique provides flexible spectral bandwidth selection and allows systematic subtraction of continuum emission from line emission images

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.

Whole body imaging

International Nuclear Information System (INIS)

de Luca, P.C.; Stoddart, H.F.; Jeffries, D.

1976-01-01

A whole body imaging system rapidly forms a quality image of the bony structure, soft tissue or specific organs of a patient who has been injected with a suitable radioactive tracer chemical. A radiation detector head assembly includes a number of detector subassemblies, each having a lead collimator with tapered holes for admitting gamma radiation from a small area of the patient to a scintillation crystal that converts the gamma rays admitted by the collimator into visible or ultraviolet energy pulses. A photomultiplier converts these pulses into electrical pulses. A row of equally spaced detector subassemblies reciprocate within a nonreciprocating lead shield along the long axis of the array over a distance substantially equal to the separation between adjacent ones of the small areas. Associated electronic and electromechanical apparatus control the reciprocating motion and the longitudinal motion of the radiation detector head assembly, and process the photodetected signals to produce in a relatively short time a visible image of the radiant energy emanating from the whole body of the patient scanned

Spatial light modulator array with heat minimization and image enhancement features

Science.gov (United States)

Jain, Kanti [Briarcliff Manor, NY; Sweatt, William C [Albuquerque, NM; Zemel, Marc [New Rochelle, NY

2007-01-30

An enhanced spatial light modulator (ESLM) array, a microelectronics patterning system and a projection display system using such an ESLM for heat-minimization and resolution enhancement during imaging, and the method for fabricating such an ESLM array. The ESLM array includes, in each individual pixel element, a small pixel mirror (reflective region) and a much larger pixel surround. Each pixel surround includes diffraction-grating regions and resolution-enhancement regions. During imaging, a selected pixel mirror reflects a selected-pixel beamlet into the capture angle of a projection lens, while the diffraction grating of the pixel surround redirects heat-producing unused radiation away from the projection lens. The resolution-enhancement regions of selected pixels provide phase shifts that increase effective modulation-transfer function in imaging. All of the non-selected pixel surrounds redirect all radiation energy away from the projection lens. All elements of the ESLM are fabricated by deposition, patterning, etching and other microelectronic process technologies.

HIGH-SPEED IMAGING AND WAVEFRONT SENSING WITH AN INFRARED AVALANCHE PHOTODIODE ARRAY

Energy Technology Data Exchange (ETDEWEB)

Baranec, Christoph; Atkinson, Dani; Hall, Donald; Jacobson, Shane; Chun, Mark [Institute for Astronomy, University of Hawai‘i at Mānoa, Hilo, HI 96720-2700 (United States); Riddle, Reed [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Law, Nicholas M., E-mail: baranec@hawaii.edu [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255 (United States)

2015-08-10

Infrared avalanche photodiode (APD) arrays represent a panacea for many branches of astronomy by enabling extremely low-noise, high-speed, and even photon-counting measurements at near-infrared wavelengths. We recently demonstrated the use of an early engineering-grade infrared APD array that achieves a correlated double sampling read noise of 0.73 e{sup −} in the lab, and a total noise of 2.52 e{sup −} on sky, and supports simultaneous high-speed imaging and tip-tilt wavefront sensing with the Robo-AO visible-light laser adaptive optics (AO) system at the Palomar Observatory 1.5 m telescope. Here we report on the improved image quality simultaneously achieved at visible and infrared wavelengths by using the array as part of an image stabilization control loop with AO-sharpened guide stars. We also discuss a newly enabled survey of nearby late M-dwarf multiplicity, as well as future uses of this technology in other AO and high-contrast imaging applications.

A position-sensitive scintillation detector for two-dimensional angular correlation of annihilation radiation using metal-package position-sensitive photomultiplier tubes

International Nuclear Information System (INIS)

Inoue, Koji; Nagai, Yasuyoshi; Saito, Haruo; Nagashima, Yasuyuki; Hyodo, Toshio; Muramatsu, Shinichi; Nagai, Shota

1999-01-01

We have constructed and tested a prototype of a new position sensitive γ-ray detector which consists of an array of 2.6x2.6x18 mm 3 BGO scintillator blocks, a light guide, and four metal-package position-sensitive photomultiplier tubes (R5900-00-C8) recently developed by Hamamatsu Photonics Co. Ltd. Scalability of the detector of this type makes it possible to construct a larger detector using many PS-PMTs, which will be useful for the two-dimensional angular correlation of annihilation radiation apparatus

Development of a spherically focused phased array transducer for ultrasonic image-guided hyperthermia.

Science.gov (United States)

Liu, Jingfei; Foiret, Josquin; Stephens, Douglas N; Le Baron, Olivier; Ferrara, Katherine W

2016-07-21

A 1.5 MHz prolate spheroidal therapeutic array with 128 circular elements was designed to accommodate standard imaging arrays for ultrasonic image-guided hyperthermia. The implementation of this dual-array system integrates real-time therapeutic and imaging functions with a single ultrasound system (Vantage 256, Verasonics). To facilitate applications involving small animal imaging and therapy the array was designed to have a beam depth of field smaller than 3.5 mm and to electronically steer over distances greater than 1 cm in both the axial and lateral directions. In order to achieve the required f number of 0.69, 1-3 piezocomposite modules were mated within the transducer housing. The performance of the prototype array was experimentally evaluated with excellent agreement with numerical simulation. A focal volume (2.70 mm (axial)  ×  0.65 mm (transverse)  ×  0.35 mm (transverse)) defined by the  -6 dB focal intensity was obtained to address the dimensions needed for small animal therapy. An electronic beam steering range defined by the  -3 dB focal peak intensity (17 mm (axial)  ×  14 mm (transverse)  ×  12 mm (transverse)) and  -8 dB lateral grating lobes (24 mm (axial)  ×  18 mm (transverse)  ×  16 mm (transverse)) was achieved. The combined testing of imaging and therapeutic functions confirmed well-controlled local heating generation and imaging in a tissue mimicking phantom. This dual-array implementation offers a practical means to achieve hyperthermia and ablation in small animal models and can be incorporated within protocols for ultrasound-mediated drug delivery.

Development of a spherically focused phased array transducer for ultrasonic image-guided hyperthermia

Science.gov (United States)

Liu, Jingfei; Foiret, Josquin; Stephens, Douglas N.; Le Baron, Olivier; Ferrara, Katherine W.

2016-07-01

A 1.5 MHz prolate spheroidal therapeutic array with 128 circular elements was designed to accommodate standard imaging arrays for ultrasonic image-guided hyperthermia. The implementation of this dual-array system integrates real-time therapeutic and imaging functions with a single ultrasound system (Vantage 256, Verasonics). To facilitate applications involving small animal imaging and therapy the array was designed to have a beam depth of field smaller than 3.5 mm and to electronically steer over distances greater than 1 cm in both the axial and lateral directions. In order to achieve the required f number of 0.69, 1-3 piezocomposite modules were mated within the transducer housing. The performance of the prototype array was experimentally evaluated with excellent agreement with numerical simulation. A focal volume (2.70 mm (axial)  ×  0.65 mm (transverse)  ×  0.35 mm (transverse)) defined by the  -6 dB focal intensity was obtained to address the dimensions needed for small animal therapy. An electronic beam steering range defined by the  -3 dB focal peak intensity (17 mm (axial)  ×  14 mm (transverse)  ×  12 mm (transverse)) and  -8 dB lateral grating lobes (24 mm (axial)  ×  18 mm (transverse)  ×  16 mm (transverse)) was achieved. The combined testing of imaging and therapeutic functions confirmed well-controlled local heating generation and imaging in a tissue mimicking phantom. This dual-array implementation offers a practical means to achieve hyperthermia and ablation in small animal models and can be incorporated within protocols for ultrasound-mediated drug delivery.

Automatic test system of the photomultipliers

International Nuclear Information System (INIS)

Shiino, Kazuo; Kono, Koji; Ishii, Takanobu; Kasai, Seiji; Yamada, Sakue; Kitamura, Shoichi.

1990-03-01

A test system of R580 photomultipliers (PMTs) was constructed for the ZEUS experiment HERA. In this report, we will describe the general feature of the test system, each component of the setup, the procedure of the measurements, the data analyses and the results of the first 800 PMT measurements. (author)

Performance study of Philips digital silicon photomultiplier coupled to scintillating crystals

CERN Document Server

Liu, Z.; Auffray, E.; Lecoq, P.; Paganoni, M.

2016-01-01

Silicon photomultipliers (SiPMs) and scintillators are often arranged in the shape of arrays in Positron Emission Tomography (PET) systems. Digital SiPMs provide signal readout in single photon avalanche diode (SPAD) level. From the photon count rate measurement of each SPAD cell of digital SiPM, we found that the output scintillating photons distribute in an area larger than the scintillator physical coupling area. Taking advantage of the possibility to enable/disable individual cells of the digital SiPM, a group of Lutetium-yttrium oxyorthosilicate (LYSO) crystals with different dimensions coupled to a digital SiPM was used to study the influence of using different SiPM active area on the number of photons detected, energy resolution and coincidence time resolution (CTR). For the same crystal coupled to the digital SiPM, the larger the active area of digital SiPM, the higher the number of photons detected. The larger active area of the digital SiPM also results in a better energy resolution after saturation...

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)

Research on Wide-field Imaging Technologies for Low-frequency Radio Array

Science.gov (United States)

Lao, B. Q.; An, T.; Chen, X.; Wu, X. C.; Lu, Y.

2017-09-01

Wide-field imaging of low-frequency radio telescopes are subject to a number of difficult problems. One particularly pernicious problem is the non-coplanar baseline effect. It will lead to distortion of the final image when the phase of w direction called w-term is ignored. The image degradation effects are amplified for telescopes with the wide field of view. This paper summarizes and analyzes several w-term correction methods and their technical principles. Their advantages and disadvantages have been analyzed after comparing their computational cost and computational complexity. We conduct simulations with two of these methods, faceting and w-projection, based on the configuration of the first-phase Square Kilometre Array (SKA) low frequency array. The resulted images are also compared with the two-dimensional Fourier transform method. The results show that image quality and correctness derived from both faceting and w-projection are better than the two-dimensional Fourier transform method in wide-field imaging. The image quality and run time affected by the number of facets and w steps have been evaluated. The results indicate that the number of facets and w steps must be reasonable. Finally, we analyze the effect of data size on the run time of faceting and w-projection. The results show that faceting and w-projection need to be optimized before the massive amounts of data processing. The research of the present paper initiates the analysis of wide-field imaging techniques and their application in the existing and future low-frequency array, and fosters the application and promotion to much broader fields.

Linear array implementation of the EM algorithm for PET image reconstruction

International Nuclear Information System (INIS)

Rajan, K.; Patnaik, L.M.; Ramakrishna, J.

1995-01-01

The PET image reconstruction based on the EM algorithm has several attractive advantages over the conventional convolution back projection algorithms. However, the PET image reconstruction based on the EM algorithm is computationally burdensome for today's single processor systems. In addition, a large memory is required for the storage of the image, projection data, and the probability matrix. Since the computations are easily divided into tasks executable in parallel, multiprocessor configurations are the ideal choice for fast execution of the EM algorithms. In tis study, the authors attempt to overcome these two problems by parallelizing the EM algorithm on a multiprocessor systems. The parallel EM algorithm on a linear array topology using the commercially available fast floating point digital signal processor (DSP) chips as the processing elements (PE's) has been implemented. The performance of the EM algorithm on a 386/387 machine, IBM 6000 RISC workstation, and on the linear array system is discussed and compared. The results show that the computational speed performance of a linear array using 8 DSP chips as PE's executing the EM image reconstruction algorithm is about 15.5 times better than that of the IBM 6000 RISC workstation. The novelty of the scheme is its simplicity. The linear array topology is expandable with a larger number of PE's. The architecture is not dependant on the DSP chip chosen, and the substitution of the latest DSP chip is straightforward and could yield better speed performance

Real-time 3D imaging methods using 2D phased arrays based on synthetic focusing techniques.

Science.gov (United States)

Kim, Jung-Jun; Song, Tai-Kyong

2008-07-01

A fast 3D ultrasound imaging technique using a 2D phased array transducer based on the synthetic focusing method for nondestructive testing or medical imaging is proposed. In the proposed method, each column of a 2D array is fired successively to produce transverse fan beams focused at a fixed depth along a given longitudinal direction and the resulting pulse echoes are received at all elements of a 2D array used. After firing all column arrays, a frame of high-resolution image along a given longitudinal direction is obtained with dynamic focusing employed in the longitudinal direction on receive and in the transverse direction on both transmit and receive. The volume rate of the proposed method can be increased much higher than that of the conventional 2D array imaging by employing an efficient sparse array technique. A simple modification to the proposed method can further increase the volume scan rate significantly. The proposed methods are verified through computer simulations.

Large-format InGaAs focal plane arrays for SWIR imaging

Science.gov (United States)

Hood, Andrew D.; MacDougal, Michael H.; Manzo, Juan; Follman, David; Geske, Jonathan C.

2012-06-01

FLIR Electro Optical Components will present our latest developments in large InGaAs focal plane arrays, which are used for low light level imaging in the short wavelength infrared (SWIR) regime. FLIR will present imaging from their latest small pitch (15 μm) focal plane arrays in VGA and High Definition (HD) formats. FLIR will present characterization of the FPA including dark current measurements as well as the use of correlated double sampling to reduce read noise. FLIR will show imagery as well as FPA-level characterization data.

Improved Focusing Method for 3-D Imaging using Row–Column-Addressed 2-D Arrays

DEFF Research Database (Denmark)

Bouzari, Hamed; Engholm, Mathias; Stuart, Matthias Bo

2017-01-01

A row–column-addressed (RCA) 2-D array can be interpreted as two orthogonal 1-D arrays. By transmitting with row elements and receiving the echoes through column elements or vice versa, a rectilinear volume in front of the array can be beamformed. Since the transmit and receive 1-D arrays are ort...... measurements with a PZT λ/2-pitch 3 MHz 62+62 RCA 2-D transducer probe. A synthetic aperture imaging sequence with single element transmissions at a time, is designed for imaging down to 14 cm at a volume rate of 44 Hz....

A camac based data acquisition system for flat-panel image array readout

International Nuclear Information System (INIS)

Morton, E.J.; Antonuk, L.E.; Berry, J.E.; Huang, W.; Mody, P.; Yorkston, J.; Longo, M.J.

1993-01-01

A readout system has been developed to facilitate the digitization and subsequent display of image data from two-dimensional, pixellated, flat-panel, amorphous silicon imaging arrays. These arrays have been designed specifically for medical x-ray imaging applications. The readout system is based on hardware and software developed for various experiments at CERN and Fermi National Accelerator Laboratory. Additional analog signal processing and digital control electronics were constructed specifically for this application. The authors report on the form of the resulting data acquisition system, discuss aspects of its performance, and consider the compromises which were involved in its design

Smart-phone based computational microscopy using multi-frame contact imaging on a fiber-optic array.

Science.gov (United States)

Navruz, Isa; Coskun, Ahmet F; Wong, Justin; Mohammad, Saqib; Tseng, Derek; Nagi, Richie; Phillips, Stephen; Ozcan, Aydogan

2013-10-21

We demonstrate a cellphone based contact microscopy platform, termed Contact Scope, which can image highly dense or connected samples in transmission mode. Weighing approximately 76 grams, this portable and compact microscope is installed on the existing camera unit of a cellphone using an opto-mechanical add-on, where planar samples of interest are placed in contact with the top facet of a tapered fiber-optic array. This glass-based tapered fiber array has ~9 fold higher density of fiber optic cables on its top facet compared to the bottom one and is illuminated by an incoherent light source, e.g., a simple light-emitting-diode (LED). The transmitted light pattern through the object is then sampled by this array of fiber optic cables, delivering a transmission image of the sample onto the other side of the taper, with ~3× magnification in each direction. This magnified image of the object, located at the bottom facet of the fiber array, is then projected onto the CMOS image sensor of the cellphone using two lenses. While keeping the sample and the cellphone camera at a fixed position, the fiber-optic array is then manually rotated with discrete angular increments of e.g., 1-2 degrees. At each angular position of the fiber-optic array, contact images are captured using the cellphone camera, creating a sequence of transmission images for the same sample. These multi-frame images are digitally fused together based on a shift-and-add algorithm through a custom-developed Android application running on the smart-phone, providing the final microscopic image of the sample, visualized through the screen of the phone. This final computation step improves the resolution and also removes spatial artefacts that arise due to non-uniform sampling of the transmission intensity at the fiber optic array surface. We validated the performance of this cellphone based Contact Scope by imaging resolution test charts and blood smears.

High-resolution 3D laser imaging based on tunable fiber array link

Science.gov (United States)

Zhao, Sisi; Ruan, Ningjuan; Yang, Song

2017-10-01

Airborne photoelectric reconnaissance system with the bore sight down to the ground is an important battlefield situational awareness system, which can be used for reconnaissance and surveillance of complex ground scene. Airborne 3D imaging Lidar system is recognized as the most potential candidates for target detection under the complex background, and is progressing in the directions of high resolution, long distance detection, high sensitivity, low power consumption, high reliability, eye safe and multi-functional. However, the traditional 3D laser imaging system has the disadvantages of lower imaging resolutions because of the small size of the existing detector, and large volume. This paper proposes a high resolution laser 3D imaging technology based on the tunable optical fiber array link. The echo signal is modulated by a tunable optical fiber array link and then transmitted to the focal plane detector. The detector converts the optical signal into electrical signals which is given to the computer. Then, the computer accomplishes the signal calculation and image restoration based on modulation information, and then reconstructs the target image. This paper establishes the mathematical model of tunable optical fiber array signal receiving link, and proposes the simulation and analysis of the affect factors on high density multidimensional point cloud reconstruction.

Conceptual design and optimization of a plastic scintillator array for 2D tomography using a compact D-D fast neutron generator.

Science.gov (United States)

Adams, Robert; Zboray, Robert; Cortesi, Marco; Prasser, Horst-Michael

2014-04-01

A conceptual design optimization of a fast neutron tomography system was performed. The system is based on a compact deuterium-deuterium fast neutron generator and an arc-shaped array of individual neutron detectors. The array functions as a position sensitive one-dimensional detector allowing tomographic reconstruction of a two-dimensional cross section of an object up to 10 cm across. Each individual detector is to be optically isolated and consists of a plastic scintillator and a Silicon Photomultiplier for measuring light produced by recoil protons. A deterministic geometry-based model and a series of Monte Carlo simulations were used to optimize the design geometry parameters affecting the reconstructed image resolution. From this, it is expected that with an array of 100 detectors a reconstructed image resolution of ~1.5mm can be obtained. Other simulations were performed in order to optimize the scintillator depth (length along the neutron path) such that the best ratio of direct to scattered neutron counts is achieved. This resulted in a depth of 6-8 cm and an expected detection efficiency of 33-37%. Based on current operational capabilities of a prototype neutron generator being developed at the Paul Scherrer Institute, planned implementation of this detector array design should allow reconstructed tomograms to be obtained with exposure times on the order of a few hours. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Topological Array Trigger for AGIS, the Advanced Gamma ray Imaging System

Science.gov (United States)

Krennrich, F.; Anderson, J.; Buckley, J.; Byrum, K.; Dawson, J.; Drake, G.; Haberichter, W.; Imran, A.; Krawczynski, H.; Kreps, A.; Schroedter, M.; Smith, A.

2008-12-01

Next generation ground based γ-ray observatories such as AGIS1 and CTA2 are expected to cover a 1 km2 area with 50-100 imaging atmospheric Cherenkov telescopes. The stereoscopic view ol air showers using multiple view points raises the possibility to use a topological array trigger that adds substantial flexibility, new background suppression capabilities and a reduced energy threshold. In this paper we report on the concept and technical implementation of a fast topological trigger system, that makes use of real time image processing of individual camera patterns and their combination in a stereoscopic array analysis. A prototype system is currently under construction and we discuss the design and hardware of this topological array trigger system.

A small animal PET prototype based on Silicon Photomultipliers

International Nuclear Information System (INIS)

Marcatili, S; Belcari, N.; Bisogni, M.G.; Del Guerra, A.; Collazuol, G.; Pedreschi, E.; Spinella, F.; Sportelli, G.; Marzocca, C.

2011-01-01

Next generation PET scanners should full fill very high requirements in terms of spatial, energy and timing resolution. Modern scanner performances are inherently limited by the use of standard photomultiplier tubes. The use of Silicon Photomultiplier (Si P M) matrices is proposed for the construction of a small animal PET system consisting of two detector heads based on Lyso continuos crystals. The use of large area multi-pixel Silicon Photomultiplier (Si P M) detectors requires the development of a multichannel Digital Acquisition system (DAQ) as well as of a dedicated front-end in order not to degrade the intrinsic detector capabilities. At the University of Pisa and INFN Pisa we developed a DAQ board for the read-out of 2 64-pixel Si P M matrices in time coincidence for Positron Emission Tomography (PET) applications. The proof of principles is based on 64-pixel detectors, but the whole system has been conceived to be easily scalable to a higher number of channels. Here we describe the Group-V INFN DASi P M 2 (Development and Application of Si P M) project and related results.

Fast photomultiplier ELUP 151

International Nuclear Information System (INIS)

Andreeva, L.I.; Belokon', V.A.; Krasin, E.V.

1992-01-01

High-velocity photomultiplier is described. The latter is recommended to be used in nuclear physics, plasma physics, nuclear medical diagnostics and at measurement of fast-occurring process parameters. Main specifications are as follows: range of spectral sensitivity - 0.2-0.7 μm; limit of dinamic characteristic linearity - up to 5A; dark current at +20 deg C ambient temperature - maximum 10-8A, time of anode pulse growth - maximum 8 ns; photocathode quantum yield in the maximum of spectral characteristic (λ max =380-420 nm) - 24-26%; supply voltage - 4-5 kV

A time-of-flight array for 1 to 2 GeV/c particles

International Nuclear Information System (INIS)

Sum, V.; Berdoz, A.R.; Davis, C.A.

1992-09-01

A time-of-flight detector array has been developed for an experiment searching for the strangeness -2 H-particle. The array consists of 40 logs of plastic scintillator with dimensions 2.00 x 0.085 x 0.050 m 3 . The photomultiplier tubes are coupled to the scintillators without the use of light guides, and the mounting of the bars is designed for easy adjustment and servicing. The average intrinsic time resolution was found to be 110 ps σ. 8 refs., 9 figs., 1 tab

A time-of-flight array for 1 to 2 GeV/c particles

Energy Technology Data Exchange (ETDEWEB)

Sum, V; Berdoz, A R; Davis, C A [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Physics; and others

1992-09-01

A time-of-flight detector array has been developed for an experiment searching for the strangeness -2 H-particle. The array consists of 40 logs of plastic scintillator with dimensions 2.00 x 0.085 x 0.050 m{sup 3}. The photomultiplier tubes are coupled to the scintillators without the use of light guides, and the mounting of the bars is designed for easy adjustment and servicing. The average intrinsic time resolution was found to be 110 ps {sigma}. 8 refs., 9 figs., 1 tab.

Muon counting using silicon photomultipliers in the AMIGA detector of the Pierre Auger observatory

Science.gov (United States)

Aab, A.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Samarai, I. Al; Albuquerque, I. F. M.; Allekotte, I.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Ambrosio, M.; Anastasi, G. A.; Anchordoqui, L.; Andrada, B.; Andringa, S.; Aramo, C.; Arqueros, F.; Arsene, N.; Asorey, H.; Assis, P.; Aublin, J.; Avila, G.; Badescu, A. M.; Balaceanu, A.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou, X.; Biermann, P. L.; Billoir, P.; Biteau, J.; Blaess, S. G.; Blanco, A.; Blazek, J.; Bleve, C.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Borodai, N.; Botti, A. M.; Brack, J.; Brancus, I.; Bretz, T.; Bridgeman, A.; Briechle, F. L.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Cancio, A.; Canfora, F.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Clay, R. W.; Colalillo, R.; Coleman, A.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Cronin, J.; Dallier, R.; D'Amico, S.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; de Jong, S. J.; De Mauro, G.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; Debatin, J.; del Peral, L.; Deligny, O.; Di Giulio, C.; Di Matteo, A.; Díaz Castro, M. L.; Diogo, F.; Dobrigkeit, C.; D'Olivo, J. C.; Dorofeev, A.; dos Anjos, R. C.; Dova, M. T.; Dundovic, A.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Fratu, O.; Freire, M. M.; Fujii, T.; Fuster, A.; García, B.; Garcia-Pinto, D.; Gaté, F.; Gemmeke, H.; Gherghel-Lascu, A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Głas, D.; Glaser, C.; Glass, H.; Golup, G.; Gómez Berisso, M.; Gómez Vitale, P. F.; González, N.; Gookin, B.; Gordon, J.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grillo, A. F.; Grubb, T. D.; Guarino, F.; Guedes, G. P.; Hampel, M. R.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Hasankiadeh, Q.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huege, T.; Hulsman, J.; Insolia, A.; Isar, P. G.; Jandt, I.; Jansen, S.; Johnsen, J. A.; Josebachuili, M.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Keilhauer, B.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Kuempel, D.; Kukec Mezek, G.; Kunka, N.; Kuotb Awad, A.; LaHurd, D.; Latronico, L.; Lauscher, M.; Lebrun, P.; Legumina, R.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; Lopes, L.; López, R.; López Casado, A.; Luce, Q.; Lucero, A.; Malacari, M.; Mallamaci, M.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Mariş, I. C.; Marsella, G.; Martello, D.; Martinez, H.; Martínez Bravo, O.; Masías Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melo, D.; Menshikov, A.; Messina, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Mockler, D.; Molina-Bueno, L.; Mollerach, S.; Montanet, F.; Morello, C.; Mostafá, M.; Müller, G.; Muller, M. A.; Müller, S.; Naranjo, I.; Navas, S.; Nellen, L.; Neuser, J.; Nguyen, P. H.; Niculescu-Oglinzanu, M.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, H.; Núñez, L. A.; Ochilo, L.; Oikonomou, F.; Olinto, A.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Papenbreer, P.; Parente, G.; Parra, A.; Paul, T.; Pech, M.; Pedreira, F.; Pȩkala, J.; Pelayo, R.; Peña-Rodriguez, J.; Pereira, L. A. S.; Perrone, L.; Peters, C.; Petrera, S.; Phuntsok, J.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porowski, C.; Prado, R. R.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Ramos-Pollant, R.; Rautenberg, J.; Ravignani, D.; Reinert, D.; Revenu, B.; Ridky, J.; Risse, M.; Ristori, P.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Rogozin, D.; Rosado, J.; Roth, M.; Roulet, E.; Rovero, A. C.; Saffi, S. J.; Saftoiu, A.; Salazar, H.; Saleh, A.; Salesa Greus, F.; Salina, G.; Sanabria Gomez, J. D.; Sánchez, F.; Sanchez-Lucas, P.; Santos, E. M.; Santos, E.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Scarso, C.; Schauer, M.; Scherini, V.; Schieler, H.; Schmidt, D.; Scholten, O.; Schovánek, P.; Schröder, F. G.; Schulz, A.; Schulz, J.; Schumacher, J.; Sciutto, S. J.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sigl, G.; Silli, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sonntag, S.; Sorokin, J.; Squartini, R.; Stanca, D.; Stanič, S.; Stasielak, J.; Strafella, F.; Suarez, F.; Suarez Durán, M.; Sudholz, T.; Suomijärvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Taborda, O. A.; Tapia, A.; Tepe, A.; Theodoro, V. M.; Timmermans, C.; Todero Peixoto, C. J.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Torri, M.; Travnicek, P.; Trini, M.; Ulrich, R.; Unger, M.; Urban, M.; Valbuena-Delgado, A.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van Bodegom, P.; van den Berg, A. M.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Villaseñor, L.; Vorobiov, S.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weindl, A.; Wiencke, L.; Wilczyński, H.; Winchen, T.; Wittkowski, D.; Wundheiler, B.; Wykes, S.; Yang, L.; Yelos, D.; Yushkov, A.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zepeda, A.; Zimmermann, B.; Ziolkowski, M.; Zong, Z.; Zuccarello, F.

2017-03-01

AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory designed to extend its energy range of detection and to directly measure the muon content of the cosmic ray primary particle showers. The array will be formed by an infill of surface water-Cherenkov detectors associated with buried scintillation counters employed for muon counting. Each counter is composed of three scintillation modules, with a 10 m2 detection area per module. In this paper, a new generation of detectors, replacing the current multi-pixel photomultiplier tube (PMT) with silicon photo sensors (aka. SiPMs), is proposed. The selection of the new device and its front-end electronics is explained. A method to calibrate the counting system that ensures the performance of the detector is detailed. This method has the advantage of being able to be carried out in a remote place such as the one where the detectors are deployed. High efficiency results, i.e. 98% efficiency for the highest tested overvoltage, combined with a low probability of accidental counting (~2%), show a promising performance for this new system.

Accuracy of single photoelectron time spread measurement of fast photomultipliers

International Nuclear Information System (INIS)

Leskovar, B.

1975-01-01

The accuracy of time spread measurements of fast photomultipliers was investigated, using single photoelectrons. The effect of the finite light pulse width on the measurement accuracy was determined and discussed. Experimental data were obtained on a special measuring system for light pulse widths ranging from 200 psec to 10 nsec, using fast photomultipliers 8850 and C31024 with optimized operating conditions for minimum transit time spread. A modified exponential function expression and curve-fitting parameters are given, which fit closely the experimentally obtained data over a wide dynamic range of light pulse widths. (U.S.)

Preliminary In-Vivo Evaluation of Convex Array Synthetic Aperture Imaging

DEFF Research Database (Denmark)

Pedersen, Morten Høgholm; Gammelmark, Kim; Jensen, Jørgen Arendt

2004-01-01

of STA imaging in comparison to conventional imaging. The purpose is to evaluate whether STA imaging is feasible in-vivo. and whether the image quality obtained is comparable to traditional scanned imaging in terms of penetration depth, spatial resolution, contrast resolution, and artifacts. Acquisition...... was done using our RASMUS research scanner and a 5.5 MHz convex array transducer. STA imaging applies spherical wave emulation using multi-element subapertures and a 20 mus linear FM signal as excitation pulse. For conventional imaging a 64 element aperture was used in transmit and receive with a 1.5 cycle...

Image Reconstruction in Radio Astronomy with Non-Coplanar Synthesis Arrays

Science.gov (United States)

Goodrick, L.

2015-03-01

Traditional radio astronomy imaging techniques assume that the interferometric array is coplanar, with a small field of view, and that the two-dimensional Fourier relationship between brightness and visibility remains valid, allowing the Fast Fourier Transform to be used. In practice, to acquire more accurate data, the non-coplanar baseline effects need to be incorporated, as small height variations in the array plane introduces the w spatial frequency component. This component adds an additional phase shift to the incoming signals. There are two approaches to account for the non-coplanar baseline effects: either the full three-dimensional brightness and visibility model can be used to reconstruct an image, or the non-coplanar effects can be removed, reducing the three dimensional relationship to that of the two-dimensional one. This thesis describes and implements the w-projection and w-stacking algorithms. The aim of these algorithms is to account for the phase error introduced by non-coplanar synthesis arrays configurations, making the recovered visibilities more true to the actual brightness distribution model. This is done by reducing the 3D visibilities to a 2D visibility model. The algorithms also have the added benefit of wide-field imaging, although w-stacking supports a wider field of view at the cost of more FFT bin support. For w-projection, the w-term is accounted for in the visibility domain by convolving it out of the problem with a convolution kernel, allowing the use of the two-dimensional Fast Fourier Transform. Similarly, the w-Stacking algorithm applies a phase correction in the image domain to image layers to produce an intensity model that accounts for the non-coplanar baseline effects. This project considers the KAT7 array for simulation and analysis of the limitations and advantages of both the algorithms. Additionally, a variant of the Högbom CLEAN algorithm was used which employs contour trimming for extended source emission flagging. The

Photomultiplier tube having a plurality of sensing areas

International Nuclear Information System (INIS)

1976-01-01

A single photomultiplier tube having four sensing areas each of which produces its own independent electrical signal that is related to the quantity of sensed matter that impinges on its area is described

Characterisation of the Hamamatsu photomultipliers for the KM3NeT Neutrino Telescope

NARCIS (Netherlands)

Aiello, S.; Akrame, S.E.; Amélineau, F.; Anassontzis, E.G.; Andre, M.; Androulakis, G.; Anghinolfi; Anton, G.; Ardid, M.; Aublin, J.; Avgitas, T.; Baars, M.; Bagatelas, C.; Barbarino, G.; Baret, B.; Barrios-Martí, J.; Belias, A.; Berbee, E.; van den Berg, A.; Bertin, V.; Biagi, S.; Biagioni, A.; Biernoth, C.; Bormuth, R.; Boumaaza, J.; Bourret, S.; Bouwhuis, M.; Bozza, C.; Brânzas, H.; Briukhanova, N.; Bruijn, R.; Brunner, J.; Buis, E.; Buompane, R,; Busto, J.; Calvo, D.; Capone, A.; Caramete, L.; Celli, S.; Chabab, M.; Cherubini, S.; Chiarella, V.; Chiarusi, T.; Circella, M.; Cocimano, R.; Coelho, J.A.B.; Coleiro, A.; Molla, M.C.; Coniglione, R.; Coyle, P.; Creusot, A.; Cuttone, G.; D’Onofrio, A.; Dallier, R.; De Sio, C.; Di Palma, I.; Díaz, A.F.; Distefano, C.; Domi, A.; Donà, R.; Donzaud, C.; Dornic, D.; Dörr, M.; Durocher, M.; Eberl, T.; Van Eijk, D.; El Bojaddaini, I.; Elsaesser, D.; Enzenhöfer, A.; Ferrara, G.; Fusco, L.A.; Gal, T.; Garufi, F.; Gauchery, S.; Geißelsöder, S.; Gialanella, L.; Giorgio, E.; Giuliante, A.; Gozzini, S.R.; Gracia-Ruiz, R.; Graf, K.; Grasso, D.; Grégoire, T.; Grella, G.; Hallmann, S.; van Haren, H.; Heid, T.; Heijboer, A.; Hekalo, A.; Hernandez-Rey, J.J.; Hofestädt, J.; Illuminati, G.; James, C.W.; Jongen, M.; Jongewaard, B.; de Jong, M.; de Jong, P.; Kadler, M.; Kalaczynski, P.; Kalekin, O.; Katz, U.F.; Khan Chowdhury, N.R.; Kieft, G.; Kießling, D.; Koffeman, E.N.; Kooijman, P.; Kouchner, A.; Kreter, M.; Kulikovskiy, V.; Lahmann, R.; Le Breton, A.; Leone, F.; Leonora, E.; Levi, G.; Lincetto, M.; Lonardo, A.; Longhitano, F.; Lotze, M.; Loucatos, S.; Maggi, G.; Manczak, J.; Mannheim, K.; Margiotta, A.; Marinelli, A.; Markou, C.; Martin, L.; Martínez-Mora, J.A.; Martini, A.; Marzaioli, F.; Mele, R.; Melis, K.W.; Migliozzi, P.; Migneco, E.; Mijakowski, P.; Mollo, C.M.; Morganti, M.; Moser, M.; Moussa, A.; Muller, R.; Musumeci, M.; Nauta, L.; Navas, S.; Nicolau, C.A.; Nielsen, C.; Organokov, M.; Orlando, A.; Panagopoulos, V.; Papalashvili, G.; Papaleo, R.; Pavalas, G.E.; Pellegrini, G.; Pellegrino, C.; Pérez Romero, J.; Perrin-Terrin, M.; Piattelli, P.; Pikounis, K.; Pisanti, O.; Poirè, C.; Polydefki, G.; Poma, G.E.; Popa, V.; Post, M.; Pradier, T.; Pühlhofer, G.; Pulvirenti, S.; Quinn, L.; Raffaelli, F.; Randazzo, N.; Razzaque, S.; Real, D.; Resvanis, L.; Reubelt, J.; Riccobene, G.; Richer, M.; Rovelli, A.; Salvadori, I.; Samtleben, D.F.E.; Sánchez-Losa, A.; Sanguineti, M.; Santangelo, A.; Sapienza, P.; Schermer, B.; Sciacca, V.; Seneca, J.; Sgura, I.; Shanidze, R.; Sharma, A.; Simeone, F.; Sinopoulou, A.; Spisso, B.; Spurio, M.; Stavropoulos, D.; Steijger, J.; Stellacci, S.M.; Strandberg, B.; Stransky, D.; Stüven, T.; Taiuti, M.; Tatone, F.; Tayalati, Y.; Tenllado, E.; Thakore, T.; Timmer, P.; Trovato, A.; Tsagkli, S.; Tzamariudaki, E.; Tzanetatos, D.; Valieri, C.; Vallage, B.; Van Elewyck, V.; Versari, F.; Viola, S.; Vivolo, D.; Volkert, M.; de Waardt, L.; Wilms, J.; de Wolf, E.; Zaborov, D.; Zornoza, J.D.; Zúñiga, J.

2018-01-01

The Hamamatsu R12199-02 3-inch photomultiplier tube is the photodetector chosen for the first phase of the KM3NeT neutrino telescope. About 7000 photomultipliers have been characterised for dark count rate, timing spread and spurious pulses. The quantum efficiency, the gain and the peak-to-valley

Uncooled infrared focal plane array imaging in China

Science.gov (United States)

Lei, Shuyu

2015-06-01

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

Frequency-domain imaging algorithm for ultrasonic testing by application of matrix phased arrays

Directory of Open Access Journals (Sweden)

Dolmatov Dmitry

2017-01-01

Full Text Available Constantly increasing demand for high-performance materials and systems in aerospace industry requires advanced methods of nondestructive testing. One of the most promising methods is ultrasonic imaging by using matrix phased arrays. This technique allows to create three-dimensional ultrasonic imaging with high lateral resolution. Further progress in matrix phased array ultrasonic testing is determined by the development of fast imaging algorithms. In this article imaging algorithm based on frequency domain calculations is proposed. This approach is computationally efficient in comparison with time domain algorithms. Performance of the proposed algorithm was tested via computer simulations for planar specimen with flat bottom holes.

Sampling phased array a new technique for signal processing and ultrasonic imaging

OpenAIRE

Bulavinov, A.; Joneit, D.; Kröning, M.; Bernus, L.; Dalichow, M.H.; Reddy, K.M.

2006-01-01

Different signal processing and image reconstruction techniques are applied in ultrasonic non-destructive material evaluation. In recent years, rapid development in the fields of microelectronics and computer engineering lead to wide application of phased array systems. A new phased array technique, called "Sampling Phased Array" has been developed in Fraunhofer Institute for non-destructive testing. It realizes unique approach of measurement and processing of ultrasonic signals. The sampling...

Development of a magnetic nanoparticle susceptibility magnitude imaging array

International Nuclear Information System (INIS)

Ficko, Bradley W; Nadar, Priyanka M; Hoopes, P Jack; Diamond, Solomon G

2014-01-01

There are several emerging diagnostic and therapeutic applications of magnetic nanoparticles (mNPs) in medicine. This study examines the potential for developing an mNP imager that meets these emerging clinical needs with a low cost imaging solution that uses arrays of digitally controlled drive coils in a multiple-frequency, continuous-wave operating mode and compensated fluxgate magnetometers. The design approach is described and a mathematical model is developed to support measurement and imaging. A prototype is used to demonstrate active compensation of up to 185 times the primary applied magnetic field, depth sensitivity up to 2.5 cm (p < 0.01), and linearity over five dilutions (R 2  > 0.98, p < 0.001). System frequency responses show distinguishable readouts for iron oxide mNPs with single magnetic domain core diameters of 10 and 40 nm, and multi-domain mNPs with a hydrodynamic diameter of 100 nm. Tomographic images show a contrast-to-noise ratio of 23 for 0.5 ml of 12.5 mg Fe ml −1  mNPs at 1 cm depth. A demonstration involving the injection of mNPs into pork sausage shows the potential for use in biological systems. These results indicate that the proposed mNP imaging approach can potentially be extended to a larger array system with higher-resolution. (paper)

The PhE4-49B photomultiplier spply providing the protection from the geomagnetic field

International Nuclear Information System (INIS)

Georgiev, V.V.; Gladyshev, V.A.

1980-01-01

To protect a scintillation detector from the effect of the geomagnetic field it is proposed to use an experimentally selected voltage divider in the FEhU-49B photomultiplier supplying circuit. Employment of such a divider makes it possible to increase the electrostatic field strength in the photomultiplier input chamber which ensures better collection of photoelectrons on the first dynode, to decrease effect of the magnetic field on electron focusing and to increase the first dynode secondary emission coefficient. Selection of photomultiplier supplying conditions is carried out experimentally on a scintillation counter with a plastic scintillator. The potentials of the focusing electrode and the first dynode are adjusted so that the relation between the counting rate at a photomultiplier orientation along the magnetic field lines of force and the counting rate at normal orientation to the lines of force is minimum. Usage of the experimentally selected voltage divider improves the scintillation counter time resolution and decreases the photomultiplier operating supply voltage by 100-150 V. The scintillation counter provided with a proposed divider requires no magnetic shields [ru

Coded aperture subreflector array for high resolution radar imaging

Science.gov (United States)

Lynch, Jonathan J.; Herrault, Florian; Kona, Keerti; Virbila, Gabriel; McGuire, Chuck; Wetzel, Mike; Fung, Helen; Prophet, Eric

2017-05-01

HRL Laboratories has been developing a new approach for high resolution radar imaging on stationary platforms. High angular resolution is achieved by operating at 235 GHz and using a scalable tile phased array architecture that has the potential to realize thousands of elements at an affordable cost. HRL utilizes aperture coding techniques to minimize the size and complexity of the RF electronics needed for beamforming, and wafer level fabrication and integration allow tiles containing 1024 elements to be manufactured with reasonable costs. This paper describes the results of an initial feasibility study for HRL's Coded Aperture Subreflector Array (CASA) approach for a 1024 element micromachined antenna array with integrated single-bit phase shifters. Two candidate electronic device technologies were evaluated over the 170 - 260 GHz range, GaN HEMT transistors and GaAs Schottky diodes. Array structures utilizing silicon micromachining and die bonding were evaluated for etch and alignment accuracy. Finally, the overall array efficiency was estimated to be about 37% (not including spillover losses) using full wave array simulations and measured device performance, which is a reasonable value at 235 GHz. Based on the measured data we selected GaN HEMT devices operated passively with 0V drain bias due to their extremely low DC power dissipation.

New bi-dimensional SPAD arrays for time resolved single photon imaging

Energy Technology Data Exchange (ETDEWEB)

Grasso, R. [INFN-Laboratori Nazionali del Sud and Sez., INFN di Catania, Via S. Sofia 62, 95125 Catania (Italy); Dipartimento di Fisica ed Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Viale A. Doria 6, 95125 Catania (Italy); Tudisco, S., E-mail: tudisco@lns.infn.it [INFN-Laboratori Nazionali del Sud and Sez., INFN di Catania, Via S. Sofia 62, 95125 Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Viale A. Doria 6, 95125 Catania (Italy); Piemonte, C. [FBK-Fondazione Bruno Kessler, Via S. Croce 77, 38122 Trento (Italy); Lo Presti, D. [INFN-Laboratori Nazionali del Sud and Sez., INFN di Catania, Via S. Sofia 62, 95125 Catania (Italy); Dipartimento di Fisica ed Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania (Italy); Anzalone, A. [INFN-Laboratori Nazionali del Sud and Sez., INFN di Catania, Via S. Sofia 62, 95125 Catania (Italy); Musumeci, F.; Scordino, A. [INFN-Laboratori Nazionali del Sud and Sez., INFN di Catania, Via S. Sofia 62, 95125 Catania (Italy); Dipartimento di Fisica ed Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania (Italy); Serra, N.; Zorzi, N. [FBK-Fondazione Bruno Kessler, Via S. Croce 77, 38122 Trento (Italy)

2013-08-01

Some of the first results concerning the electrical and optical performances of new bi-dimensional single photon avalanche diodes arrays for imaging applications are briefly presented. The planned arrays were realized at the Fondazione Bruno Kessler—Trento and tested at LNS–INFN. The proposed new solution, utilizing a new architecture with integrated quenching resistors, allows to simplify the electronic readout.

New bi-dimensional SPAD arrays for time resolved single photon imaging

International Nuclear Information System (INIS)

Grasso, R.; Tudisco, S.; Piemonte, C.; Lo Presti, D.; Anzalone, A.; Musumeci, F.; Scordino, A.; Serra, N.; Zorzi, N.

2013-01-01

Some of the first results concerning the electrical and optical performances of new bi-dimensional single photon avalanche diodes arrays for imaging applications are briefly presented. The planned arrays were realized at the Fondazione Bruno Kessler—Trento and tested at LNS–INFN. The proposed new solution, utilizing a new architecture with integrated quenching resistors, allows to simplify the electronic readout

Parallel image-acquisition in continuous-wave electron paramagnetic resonance imaging with a surface coil array: Proof-of-concept experiments

Science.gov (United States)

Enomoto, Ayano; Hirata, Hiroshi

2014-02-01

This article describes a feasibility study of parallel image-acquisition using a two-channel surface coil array in continuous-wave electron paramagnetic resonance (CW-EPR) imaging. Parallel EPR imaging was performed by multiplexing of EPR detection in the frequency domain. The parallel acquisition system consists of two surface coil resonators and radiofrequency (RF) bridges for EPR detection. To demonstrate the feasibility of this method of parallel image-acquisition with a surface coil array, three-dimensional EPR imaging was carried out using a tube phantom. Technical issues in the multiplexing method of EPR detection were also clarified. We found that degradation in the signal-to-noise ratio due to the interference of RF carriers is a key problem to be solved.

Development of gamma spectrometer using silicon photomultiplier (SiPM)

International Nuclear Information System (INIS)

Kim, Chan Kyu

2011-02-01

Gamma spectroscopy is used to determine the identity and quantity of gamma-emitters in nuclear physics, geochemistry and astrophysics. The scintillation detectors are being used as a gamma spectrometer generally, because of their higher gamma-ray detection efficiency and cheaper price than germanium semi-conductor detectors. A typical scintillation detector is composed of a scintillator, a window, and a photodetector. The photomultiplier (PM) tube has been the most widely used as a photodetector because of its advantages like high sensitivity, high signal-to-noise ratio, and wide dynamic range. Recently, the Silicon Photomultiplier (SiPM) is being studied as a substitute of PM tube. The SiPM has almost same performance compared to PM tube but it has additional advantages; low operating voltage, small volume, and cheap production cost. In this research, the gamma spectrometer using SiPM instead of PM tube is developed. The use of SiPM as a photodetector makes the gamma spectrometer smaller, cheaper, easier to use. For photon transport and collection from the large area scintillator to the small area SiPM, a light guide is applied in this gamma spectrometer system. Before fabrication of light guide, DETECT simulation is performed to study and prospect characteristics of light guide structure. And actual light guides are fabricated on the basis of this simulation result. Poly(methyl methacrylate) (PMMA) is chosen as material of light guide, 5 sample light guides are fabricated in different lengths and coatings. As a scintillator crystal, same NaI(Tl) crystal is chosen. For measurement and analysis of gamma spectrometer system, 3 gamma spectrometer systems are composed: PM tube-based system, PM tube-based system with the light guide, SiPM-based system with the light guide. Through comparison between the results of each gamma spectrometer, the performances of gamma spectrometer system are analyzed by each component. Measurement results of the second system is well

Segmented scintillation detectors with silicon photomultiplier readout for measuring antiproton annihilations

CERN Document Server

Sótér, A.; Kobayashi, T.; Barna, D.; Horváth, D.; Hori, M.

2014-01-01

The Atomic Spectroscopy and Collisions Using Slow Antiprotons (ASACUSA) experiment at the Antiproton Decelerator (AD) facility of CERN constructed segmented scintillators to detect and track the charged pions which emerge from antiproton annihilations in a future superconducting radiofrequency Paul trap for antiprotons. A system of 541 cast and extruded scintillator bars were arranged in 11 detector modules which provided a spatial resolution of 17 mm. Green wavelength-shifting fibers were embedded in the scintillators, and read out by silicon photomultipliers which had a sensitive area of 1 x 1 mm^2. The photoelectron yields of various scintillator configurations were measured using a negative pion beam of momentum p ~ 1 GeV/c. Various fibers and silicon photomultipliers, fiber end terminations, and couplings between the fibers and scintillators were compared. The detectors were also tested using the antiproton beam of the AD. Nonlinear effects due to the saturation of the silicon photomultiplier were seen a...

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.

Intensity correction method customized for multi-animal abdominal MR imaging with 3 T clinical scanner and multi-array coil

International Nuclear Information System (INIS)

Mitsuda, Minoru; Yamaguchi, Masayuki; Nakagami, Ryutaro; Furuta, Toshihiro; Fujii, Hirofumi; Sekine, Norio; Niitsu, Mamoru; Moriyama, Noriyuki

2013-01-01

Simultaneous magnetic resonance (MR) imaging of multiple small animals in a single session increases throughput of preclinical imaging experiments. Such imaging using a 3-tesla clinical scanner with multi-array coil requires correction of intensity variation caused by the inhomogeneous sensitivity profile of the coil. We explored a method for correcting intensity that we customized for multi-animal MR imaging, especially abdominal imaging. Our institutional committee for animal experimentation approved the protocol. We acquired high resolution T 1 -, T 2 -, and T 2 * -weighted images and low resolution proton density-weighted images (PDWIs) of 4 rat abdomens simultaneously using a 3T clinical scanner and custom-made multi-array coil. For comparison, we also acquired T 1 -, T 2 -, and T 2 * -weighted volume coil images in the same rats in 4 separate sessions. We used software created in-house to correct intensity variation. We applied thresholding to the PDWIs to produce binary images that displayed only a signal-producing area, calculated multi-array coil sensitivity maps by dividing low-pass filtered PDWIs by low-pass filtered binary images pixel by pixel, and divided uncorrected T 1 -, T 2 -, or T 2 * -weighted images by those maps to obtain intensity-corrected images. We compared tissue contrast among the liver, spinal canal, and muscle between intensity-corrected multi-array coil images and volume coil images. Our intensity correction method performed well for all pulse sequences studied and corrected variation in original multi-array coil images without deteriorating the throughput of animal experiments. Tissue contrasts were comparable between intensity-corrected multi-array coil images and volume coil images. Our intensity correction method customized for multi-animal abdominal MR imaging using a 3T clinical scanner and dedicated multi-array coil could facilitate image interpretation. (author)

Time-resolved fluorescence measurements using microlens array and area imaging devices.

Science.gov (United States)

Merk, Susanne; Lietz, Achim; Kroner, Margareta; Valler, Martin; Heilker, Ralf

2004-02-01

Time-resolved fluorescence (TRF) assay formats are frequently used technologies in high-throughput screening. In this article, we have characterised the novel Plate::Vision(2) 96-microlens array reader (Carl Zeiss Jena GmbH, Germany) and compared it to the novel LEADseeker Generation IV multimodality imaging system (LEADseeker Gen IV; Amersham Biosciences UK Ltd., UK) for applications in the TRF mode. In europium measurements using the TRF mode, the Plate::Vision displayed a limit of detection for europium of approximately 3 pM, which was comparable to two established TRF readers, the Discovery and the Victor V (both PerkinElmer Life Sciences Inc., USA). The LEADseeker's limit of detection only extended down to europium concentrations of approximately 10 pM in these experiments. For TRF resonance energy transfer (TR-FRET) experiments, a europium-biotin (Eu-biotin) conjugate was titrated with a streptavidin-allophycocyanin (SA-APC) conjugate. The Plate::Vision produced Z' values larger than 0.5 for the acceptor fluorophor emission with concentrations of Eu-biotin as low as 3 nM combined with 175 pM SA-APC. To achieve Z' values of at least 0.5 with the LEADseeker, concentrations of 10 nM Eu-biotin combined with SA-APC of at least 0.8 nM were required. In a drug screening application using TR-FRET, the energy transfer from a europium-labelled protein X (Eu-protein X) to a complex of biotinylated peptide Y with SA-APC was measured. Using the Plate::Vision, a Z' factor larger than 0.5 for the acceptor fluorophor emission was only obtained for a Eu-protein X concentration of at least 10 nM in combination with biotinylated peptide Y/SA-APC at saturating concentrations. Both the Plate::Vision and the LEADseeker show good quality results for applications in the TRF mode and enable an increased throughput based on their shortened measurement time in comparison to classic photomultiplier tube-based readers.

Realization of cantilever arrays for parallel proximity imaging

International Nuclear Information System (INIS)

Sarov, Y; Ivanov, Tz; Frank, A; Zoellner, J-P; Nikolov, N; Rangelow, I W

2010-01-01

This paper reports on the fabrication and characterisation of self-actuating, and self-sensing cantilever arrays for large-scale parallel surface scanning. Each cantilever is integrated with a sharp silicon tip, a thermal-driven bimorph actuator, and a piezoresistive deflection sensor. Thus, the tip to the sample distance can be controlled individually for each cantilever. A radius of the tips below 10 nm is obtained, which enables nanometre in-plane surface imaging by Angstrom resolution in vertical direction. The fabricated cantilever probe arrays are also applicable for large-area manipulation, sub-10 nm metrology, bottom-up synthesis, high-speed gas analysis, for different bio-applications like recognition of DNA, RNA, or various biomarkers of a single disease, etc.

A method to stabilise the performance of negatively fed KM3NeT photomultipliers

Science.gov (United States)

Adrián-Martínez, S.; Ageron, M.; Aiello, S.; Albert, A.; Ameli, F.; Anassontzis, E. G.; Andre, M.; Androulakis, G.; Anghinolfi, M.; Anton, G.; Ardid, M.; Avgitas, T.; Barbarino, G.; Barbarito, E.; Baret, B.; Barrios-Martí, J.; Belias, A.; Berbee, E.; van den Berg, A.; Bertin, V.; Beurthey, S.; van Beveren, V.; Beverini, N.; Biagi, S.; Biagioni, A.; Billault, M.; Bondì, M.; Bormuth, R.; Bouhadef, B.; Bourlis, G.; Bourret, S.; Boutonnet, C.; Bouwhuis, M.; Bozza, C.; Bruijn, R.; Brunner, J.; Buis, E.; Buompane, R.; Busto, J.; Cacopardo, G.; Caillat, L.; Calamai, M.; Calvo, D.; Capone, A.; Caramete, L.; Cecchini, S.; Celli, S.; Champion, C.; Cherubini, S.; Chiarella, V.; Chiarelli, L.; Chiarusi, T.; Circella, M.; Classen, L.; Cobas, D.; Cocimano, R.; Coelho, J. A. B.; Coleiro, A.; Colonges, S.; Coniglione, R.; Cordelli, M.; Cosquer, A.; Coyle, P.; Creusot, A.; Cuttone, G.; D'Amato, C.; D'Amico, A.; D'Onofrio, A.; De Bonis, G.; De Sio, C.; Di Capua, F.; Di Palma, I.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti-Hasankiadeh, Q.; Drakopoulou, E.; Drouhin, D.; Durocher, M.; Eberl, T.; Eichie, S.; van Eijk, D.; El Bojaddaini, I.; Elsaesser, D.; Enzenhöfer, A.; Favaro, M.; Fermani, P.; Ferrara, G.; Frascadore, G.; Furini, M.; Fusco, L. A.; Gal, T.; Galatà, S.; Garufi, F.; Gay, P.; Gebyehu, M.; Giacomini, F.; Gialanella, L.; Giordano, V.; Gizani, N.; Gracia, R.; Graf, K.; Grégoire, T.; Grella, G.; Grmek, A.; Guerzoni, M.; Habel, R.; Hallmann, S.; van Haren, H.; Harissopulos, S.; Heid, T.; Heijboer, A.; Heine, E.; Henry, S.; Hernández-Rey, J. J.; Hevinga, M.; Hofestädt, J.; Hugon, C. M. F.; Illuminati, G.; James, C. W.; Jansweijer, P.; Jongen, M.; de Jong, M.; Kadler, M.; Kalekin, O.; Kappes, A.; Katz, U. F.; Keller, P.; Kieft, G.; Kießling, D.; Koffeman, E. N.; Kooijman, P.; Kouchner, A.; Kreter, M.; Kulikovskiy, V.; Lahmann, R.; Lamare, P.; Leisos, A.; Leonora, E.; Clark, M. Lindsey; Liolios, A.; Llorens Alvarez, C. D.; Lo Presti, D.; Löhner, H.; Lonardo, A.; Lotze, M.; Loucatos, S.; Maccioni, E.; Mannheim, K.; Manzali, M.; Margiotta, A.; Margotti, A.; Marinelli, A.; Mariš, O.; Markou, C.; Martínez-Mora, J. A.; Martini, A.; Marzaioli, F.; Mele, R.; Melis, K. W.; Michael, T.; Migliozzi, P.; Migneco, E.; Mijakowski, P.; Miraglia, A.; Mollo, C. M.; Mongelli, M.; Morganti, M.; Moussa, A.; Musico, P.; Musumeci, M.; Nicolau, C. A.; Olcina, I.; Olivetto, C.; Orlando, A.; Orzelli, A.; Pancaldi, G.; Paolucci, A.; Papaikonomou, A.; Papaleo, R.; Păvălaš, G. E.; Peek, H.; Pellegrini, G.; Pellegrino, C.; Perrina, C.; Pfutzner, M.; Piattelli, P.; Pikounis, K.; Poma, G. E.; Popa, V.; Pradier, T.; Pratolongo, F.; Pühlhofer, G.; Pulvirenti, S.; Quinn, L.; Racca, C.; Raffaelli, F.; Randazzo, N.; Real, D.; Resvanis, L.; Reubelt, J.; Riccobene, G.; Rossi, C.; Rovelli, A.; Saldaña, M.; Salvadori, I.; Samtleben, D. F. E.; Sánchez García, A.; Sánchez Losa, A.; Sanguineti, M.; Santangelo, A.; Santonocito, D.; Sapienza, P.; Schimmel, F.; Schmelling, J.; Schnabel, J.; Sciacca, V.; Sedita, M.; Seitz, T.; Sgura, I.; Simeone, F.; Sipala, V.; Spisso, B.; Spurio, M.; Stavropoulos, G.; Steijger, J.; Stellacci, S. M.; Stransky, D.; Taiuti, M.; Tayalati, Y.; Terrasi, F.; Tézier, D.; Theraube, S.; Timmer, P.; Töonnis, C.; Trasatti, L.; Travaglini, R.; Trovato, A.; Tsirigotis, A.; Tzamarias, S.; Tzamariudaki, E.; Vallage, B.; Van Elewyck, V.; Vermeulen, J.; Versari, F.; Vicini, P.; Viola, S.; Vivolo, D.; Volkert, M.; Wiggers, L.; Wilms, J.; de Wolf, E.; Zachariadou, K.; Zani, S.; Zornoza, J. D.; Zúñiga, J.

2016-12-01

The KM3NeT research infrastructure, currently under construction in the Mediterranean Sea, will host neutrino telescopes for the identification of neutrino sources in the Universe and for studies of the neutrino mass hierarchy. These telescopes will house hundreds of thousands of photomultiplier tubes that will have to be operated in a stable and reliable fashion. In this context, the stability of the dark counts has been investigated for photomultiplier tubes with negative high voltage on the photocathode and held in insulating support structures made of 3D printed nylon material. Small gaps between the rigid support structure and the photomultiplier tubes in the presence of electric fields can lead to discharges that produce dark count rates that are highly variable. A solution was found by applying the same insulating varnish as used for the high voltage bases directly to the outside of the photomultiplier tubes. This transparent conformal coating provides a convenient and inexpensive method of insulation.

The recent development and study of silicon photomultiplier

International Nuclear Information System (INIS)

Saveliev, Valeri

2004-01-01

Recent developments and results from the study of a Silicon Solid State Photomultiplier (Si-PM) are presented. The basis of this new type of photodetector is a fine structure of microcells operating in the Geiger mode with an internal gain greater than 106. Common signal output allows for the detector to be operated in the proportional mode, and to reach a dynamic range of 1.5x103. Such photodetectors have shown single photon response at room temperature with a fast timing of ∼100ps. They are compact, robust and non-sensitive to magnetic fields. Results show the detection of low-intensity light in single photon mode and the detection of minimal ionizing particles using a scintillation tile for hadron calorimetry. The silicon photomultiplier is suitable for wide application in scintillation calorimetry, medical application, etc

Airship Sparse Array Antenna Radar Real Aperture Imaging Based on Compressed Sensing and Sparsity in Transform Domain

Directory of Open Access Journals (Sweden)

Li Liechen

2016-02-01

Full Text Available A conformal sparse array based on combined Barker code is designed for airship platform. The performance of the designed array such as signal-to-noise ratio is analyzed. Using the hovering characteristics of the airship, interferometry operation can be applied on the real aperture imaging results of two pulses, which can eliminate the random backscatter phase and make the image sparse in the transform domain. Building the relationship between echo and transform coefficients, the Compressed Sensing (CS theory can be introduced to solve the formula and achieving imaging. The image quality of the proposed method can reach the image formed by the full array imaging. The simulation results show the effectiveness of the proposed method.

Design of area array CCD image acquisition and display system based on FPGA

Science.gov (United States)

Li, Lei; Zhang, Ning; Li, Tianting; Pan, Yue; Dai, Yuming

2014-09-01

With the development of science and technology, CCD(Charge-coupled Device) has been widely applied in various fields and plays an important role in the modern sensing system, therefore researching a real-time image acquisition and display plan based on CCD device has great significance. This paper introduces an image data acquisition and display system of area array CCD based on FPGA. Several key technical challenges and problems of the system have also been analyzed and followed solutions put forward .The FPGA works as the core processing unit in the system that controls the integral time sequence .The ICX285AL area array CCD image sensor produced by SONY Corporation has been used in the system. The FPGA works to complete the driver of the area array CCD, then analog front end (AFE) processes the signal of the CCD image, including amplification, filtering, noise elimination, CDS correlation double sampling, etc. AD9945 produced by ADI Corporation to convert analog signal to digital signal. Developed Camera Link high-speed data transmission circuit, and completed the PC-end software design of the image acquisition, and realized the real-time display of images. The result through practical testing indicates that the system in the image acquisition and control is stable and reliable, and the indicators meet the actual project requirements.

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

International Nuclear Information System (INIS)

David, Stratos; Fysikopoulos, Eleftherios; Georgiou, Maria; Loudos, George

2015-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-05-18

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

Study of the Light Emission Process from the Double Chooz Photomultipliers

Energy Technology Data Exchange (ETDEWEB)

Calvo, E.; Cerrada, M.; Crespo, J. I.; Gil-Botella, I.; Jimenez, S.; Lopez, M.; Novella, P.; Palomares, C.; Santorelli, R.; Verdugo, A.

2012-09-13

In this document we present a study of the light emitted by the base of a Hamamatsu R7081MOD-ASSY photomultiplier (PMT) of the same type used in the Double Chooz experiment. Several characteristic features of the light signal have been found in terms of amplitude, length and pulse shape. Additional investigations on the properties of the epoxy used to cover the photomultiplier base have been carried out. A possible explanation of the light emission process is discussed at the end of the study. (Author) 1 ref.

Photomultiplier pulse Read Out system for the preshower detector of the LHCb experiment

International Nuclear Information System (INIS)

Ajaltouni, Z.; Bohner, G.; Cornat, R.; Deschamps, O.; Lecoq, J.; Monteil, S.; Perret, P.

2003-01-01

The second generation experiment for CP violation studies in B decays, LHCb, is a 20-m-long single-arm spectrometer to be installed on the future Large Hadron Collider at CERN. For its precision measurement purpose, it combines precise vertex location and particle identification, in addition to a performance trigger system able to cope with high flux. The first level of trigger is mainly based on the fast response of the calorimetric subsystem. Of major importance is the 6000 channels preshower detector that aims to validate the electromagnetic nature of calorimetric showers. It consists of two-radiation-length lead sheet in front of a scintillator plane. Scintillator signals are extracted from plastic cells using wavelength-shifting fibres coupled to multi-anode photomultiplier tubes. The preshower Read Out system has to cope with fluctuating photomultiplier pulses caused by small amounts of photoelectrons, in addition to strong constraints imposed by the 40 MHz LHC bunch-crossing frequency. A special Read Out electronics including perfect 40 MHz integrators able to shape fluctuating photomultiplier pulses has been designed, and successfully realized. The temporal shape of photomultiplier pulse and the upstream Read Out system for preshower are described in this document

Comparison of Thermal Detector Arrays for Off-Axis THz Holography and Real-Time THz Imaging

Directory of Open Access Journals (Sweden)

Erwin Hack

2016-02-01

Full Text Available In terahertz (THz materials science, imaging by scanning prevails when low power THz sources are used. However, the application of array detectors operating with high power THz sources is increasingly reported. We compare the imaging properties of four different array detectors that are able to record THz radiation directly. Two micro-bolometer arrays are designed for infrared imaging in the 8–14 μm wavelength range, but are based on different absorber materials (i vanadium oxide; (ii amorphous silicon; (iii a micro-bolometer array optimized for recording THz radiation based on silicon nitride; and (iv a pyroelectric array detector for THz beam profile measurements. THz wavelengths of 96.5 μm, 118.8 μm, and 393.6 μm from a powerful far infrared laser were used to assess the technical performance in terms of signal to noise ratio, detector response and detectivity. The usefulness of the detectors for beam profiling and digital holography is assessed. Finally, the potential and limitation for real-time digital holography are discussed.

Comparison of Thermal Detector Arrays for Off-Axis THz Holography and Real-Time THz Imaging.

Science.gov (United States)

Hack, Erwin; Valzania, Lorenzo; Gäumann, Gregory; Shalaby, Mostafa; Hauri, Christoph P; Zolliker, Peter

2016-02-06

In terahertz (THz) materials science, imaging by scanning prevails when low power THz sources are used. However, the application of array detectors operating with high power THz sources is increasingly reported. We compare the imaging properties of four different array detectors that are able to record THz radiation directly. Two micro-bolometer arrays are designed for infrared imaging in the 8-14 μm wavelength range, but are based on different absorber materials (i) vanadium oxide; (ii) amorphous silicon; (iii) a micro-bolometer array optimized for recording THz radiation based on silicon nitride; and (iv) a pyroelectric array detector for THz beam profile measurements. THz wavelengths of 96.5 μm, 118.8 μm, and 393.6 μm from a powerful far infrared laser were used to assess the technical performance in terms of signal to noise ratio, detector response and detectivity. The usefulness of the detectors for beam profiling and digital holography is assessed. Finally, the potential and limitation for real-time digital holography are discussed.

Performance of a PET detector module utilizing an array of silicon photodiodes to identify the crystal of interaction

International Nuclear Information System (INIS)

Moses, W.W.; Derenzo, S.E.; Nutt, R.; Digby, W.M.; Williams, C.W.; Andreaco, M.

1993-01-01

The authors initial performance results for a new multi-layer PET detector module consisting of an array of 3 mm square by 30 mm deep BGO crystals coupled on one end to a single photomultiplier tube and on the opposite end to an array of 3 mm square silicon photodiodes. The photomultiplier tube provides an accurate timing pulse and energy discrimination for all the crystals in the module, while the silicon photodiodes identify the crystal of interaction. When a single BGO crystal at +25 C is excited with 511 keV photons, the authors measure a photodiode signal centered at 700 electrons (e - ) with noise of 375 e - fwhm. When a four crystal/photodiode module is excited with a collimated line source of 511 keV photons, the crystal of interaction is correctly identified 82% of the time. The misidentification rate can be greatly reduced and an 8 x 8 crystal/photodiode module constructed by using thicker depletion layer photodiodes or cooling to 0 C

High-resolution dynamic pressure sensor array based on piezo-phototronic effect tuned photoluminescence imaging.

Science.gov (United States)

Peng, Mingzeng; Li, Zhou; Liu, Caihong; Zheng, Qiang; Shi, Xieqing; Song, Ming; Zhang, Yang; Du, Shiyu; Zhai, Junyi; Wang, Zhong Lin

2015-03-24

A high-resolution dynamic tactile/pressure display is indispensable to the comprehensive perception of force/mechanical stimulations such as electronic skin, biomechanical imaging/analysis, or personalized signatures. Here, we present a dynamic pressure sensor array based on pressure/strain tuned photoluminescence imaging without the need for electricity. Each sensor is a nanopillar that consists of InGaN/GaN multiple quantum wells. Its photoluminescence intensity can be modulated dramatically and linearly by small strain (0-0.15%) owing to the piezo-phototronic effect. The sensor array has a high pixel density of 6350 dpi and exceptional small standard deviation of photoluminescence. High-quality tactile/pressure sensing distribution can be real-time recorded by parallel photoluminescence imaging without any cross-talk. The sensor array can be inexpensively fabricated over large areas by semiconductor product lines. The proposed dynamic all-optical pressure imaging with excellent resolution, high sensitivity, good uniformity, and ultrafast response time offers a suitable way for smart sensing, micro/nano-opto-electromechanical systems.

Imaging corn plants with PhytoPET, a modular PET system for plant biology

Energy Technology Data Exchange (ETDEWEB)

Lee, S.; Kross, B.; McKisson, J.; McKisson, J. E.; Weisenberger, A. G.; Xi, W.; Zorn, C.; Bonito, G.; Howell, C. R.; Reid, C. D.; Crowell, A.; Cumberbatch, L. C.; Topp, C.; Smith, M. F.

2013-11-01

PhytoPET is a modular positron emission tomography (PET) system designed specifically for plant imaging. The PhytoPET design allows flexible arrangements of PET detectors based on individual standalone detector modules built from single Hamamatsu H8500 position sensitive photomultiplier tubes and pixelated LYSO arrays. We have used the PhytoPET system to perform preliminary corn plant imaging studies at the Duke University Biology Department Phytotron. Initial evaluation of the PhytoPET system to image the biodistribution of the positron emitting tracer {sup 11}C in corn plants is presented. {sup 11}CO{sub 2} is loaded into corn seedlings by a leaf-labeling cuvette and translocation of {sup 11}C-sugars is imaged by a flexible arrangement of PhytoPET modules on each side. The PhytoPET system successfully images {sup 11}C within corn plants and allows for the dynamic measurement of {sup 11}C-sugar translocation from the leaf to the roots.

PHASED ARRAY FEED CALIBRATION, BEAMFORMING, AND IMAGING

International Nuclear Information System (INIS)

Landon, Jonathan; Elmer, Michael; Waldron, Jacob; Jones, David; Stemmons, Alan; Jeffs, Brian D.; Warnick, Karl F.; Richard Fisher, J.; Norrod, Roger D.

2010-01-01

Phased array feeds (PAFs) for reflector antennas offer the potential for increased reflector field of view and faster survey speeds. To address some of the development challenges that remain for scientifically useful PAFs, including calibration and beamforming algorithms, sensitivity optimization, and demonstration of wide field of view imaging, we report experimental results from a 19 element room temperature L-band PAF mounted on the Green Bank 20 Meter Telescope. Formed beams achieved an aperture efficiency of 69% and a system noise temperature of 66 K. Radio camera images of several sky regions are presented. We investigate the noise performance and sensitivity of the system as a function of elevation angle with statistically optimal beamforming and demonstrate cancelation of radio frequency interference sources with adaptive spatial filtering.

Two-dimensional Fast ESPRIT Algorithm for Linear Array SAR Imaging

Directory of Open Access Journals (Sweden)

Zhao Yi-chao

2015-10-01

Full Text Available The linear array Synthetic Aperture Radar (SAR system is a popular research tool, because it can realize three-dimensional imaging. However, owning to limitations of the aircraft platform and actual conditions, resolution improvement is difficult in cross-track and along-track directions. In this study, a twodimensional fast Estimation of Signal Parameters by Rotational Invariance Technique (ESPRIT algorithm for linear array SAR imaging is proposed to overcome these limitations. This approach combines the Gerschgorin disks method and the ESPRIT algorithm to estimate the positions of scatterers in cross and along-rack directions. Moreover, the reflectivity of scatterers is obtained by a modified pairing method based on “region growing”, replacing the least-squares method. The simulation results demonstrate the applicability of the algorithm with high resolution, quick calculation, and good real-time response.

Recent measurements on the Hamamatsu 13 in., R8055, PhotoMultiplier Tubes

International Nuclear Information System (INIS)

Tsagli, S.; Aggouras, G.; Anassontzis, E.G.; Ball, A.E.; Chinowsky, W.; Fahrun, E.; Grammatikakis, G.; Green, C.; Grieder, P.; Katrivanos, P.; Koske, P.; Ludvig, J.; Markopoulos, E.; Minkowsky, P.; Nygren, D.; Papageorgiou, K.; Przybylski, G.; Resvanis, L.K.; Siotis, I.; Sopher, J.; Staveris, T.; Tsagli, V.; Zhukov, V.A.

2006-01-01

The key component of NESTOR, the deep-sea Cherenkov neutrino telescope, built in the Mediterranean, NW of Greece, is the optical module. The NESTOR Optical Module employs a PhotoMultiplier Tube (PMT) in a transparent glass pressure housing. The Hamamatsu PMT R8055-01, 13 in. photomultiplier was selected for NESTOR to replace the old 15'' Hamamatsu PMTs (R2018-03). Extensive tests have been made on the sensitivity, uniformity, time resolution and noise rates of 162 R8055-01 13 in. PMTs

Scintillation hodoscope with working area of 50 x 50 cm based on hodoscopic photomultipliers

International Nuclear Information System (INIS)

Borog, V.V.; Vasil'chenko, V.G.; Demekhin, A.V.; Dronov, V.V.; Rykalin, V.I.

1987-01-01

The choice of optimum designs for the sensitive elements of large hodoscopes based on hodoscopic photomultipliers is examined. The results of numerical calculations are confirmed by measurement results. The measured space resolution of one of the scintillation-hodoscope designs (with two hodoscopic photomultipliers) with a sensitive volume of 50 x 50 x 2 mm is ≤ +3 mm

Simultaneous MRI and PET imaging of a rat brain

Energy Technology Data Exchange (ETDEWEB)

Raylman, Raymond R [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States); Majewski, Stan [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Lemieux, Susan K [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States); Velan, S Sendhil [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States); Kross, Brian [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Popov, Vladimir [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Smith, Mark F [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Weisenberger, Andrew G [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Zorn, Carl [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Marano, Gary D [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States)

2006-12-21

Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI will allow the correlation of form with function. Our group is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode. Each MRI-PET detector module consists of an array of LSO detector elements coupled through a long fibre optic light guide to a single Hamamatsu flat panel position-sensitive photomultiplier tube (PSPMT). The use of light guides allows the PSPMTs to be positioned outside the bore of a 3T MRI scanner where the magnetic field is relatively small. To test the device, simultaneous MRI and PET images of the brain of a male Sprague Dawley rat injected with FDG were successfully obtained. The images revealed no noticeable artefacts in either image set. Future work includes the construction of a full ring PET scanner, improved light guides and construction of a specialized MRI coil to permit higher quality MRI imaging.

Simultaneous MRI and PET imaging of a rat brain

International Nuclear Information System (INIS)

Raylman, Raymond R; Majewski, Stan; Lemieux, Susan K; Velan, S Sendhil; Kross, Brian; Popov, Vladimir; Smith, Mark F; Weisenberger, Andrew G; Zorn, Carl; Marano, Gary D

2006-01-01

Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI will allow the correlation of form with function. Our group is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode. Each MRI-PET detector module consists of an array of LSO detector elements coupled through a long fibre optic light guide to a single Hamamatsu flat panel position-sensitive photomultiplier tube (PSPMT). The use of light guides allows the PSPMTs to be positioned outside the bore of a 3T MRI scanner where the magnetic field is relatively small. To test the device, simultaneous MRI and PET images of the brain of a male Sprague Dawley rat injected with FDG were successfully obtained. The images revealed no noticeable artefacts in either image set. Future work includes the construction of a full ring PET scanner, improved light guides and construction of a specialized MRI coil to permit higher quality MRI imaging

Design of a Compact Wideband Antenna Array for Microwave Imaging Applications

Directory of Open Access Journals (Sweden)

J. Puskely

2013-12-01

Full Text Available In the paper, wideband antenna arrays aimed at microwave imaging applications and SAR applications operating at Ka band were designed. The antenna array feeding network is realized by a low-loss SIW technology. Moreover, we have replaced the large feed network comprised of various T and Y junctions by a simple broadband network of compact size to more reduce losses in the substrate integrated waveguide and also save space on the PCB. The designed power 8-way divider is complemented by a wideband substrate integrated waveguide to a grounded coplanar waveguide transition and directly connected to the antenna elements. The measured results of antenna array are consistent with our simulation. Obtained results of the developed array demonstrated improvement compared to previously developed binary feed networks with microstrip or SIW splitters.

A new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array

Science.gov (United States)

Xia, Wenze; Ma, Yayun; Han, Shaokun; Wang, Yulin; Liu, Fei; Zhai, Yu

2018-06-01

One of the most important goals of research on three-dimensional nonscanning laser imaging systems is the improvement of the illumination system. In this paper, a new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array is proposed. This array is obtained using a fiber array connected to a laser array with each unit laser having independent control circuits. This system uses a point-to-point imaging process, which is realized using the exact corresponding optical relationship between the point-light-source array and a linear-mode avalanche photodiode array detector. The complete working process of this system is explained in detail, and the mathematical model of this system containing four equations is established. A simulated contrast experiment and two real contrast experiments which use the simplified setup without a laser array are performed. The final results demonstrate that unlike a conventional three-dimensional nonscanning laser imaging system, the proposed system meets all the requirements of an eligible illumination system. Finally, the imaging performance of this system is analyzed under defocusing situations, and analytical results show that the system has good defocusing robustness and can be easily adjusted in real applications.

Array scanner as microdensitometer surrogate: a deal with the devil or . . . a great deal?

Science.gov (United States)

Williams, Donald R.

2005-01-01

Inexpensive and easy-to-use linear and area-array scanners have frequently substituted as densitometers for low-frequency (i.e., large-area) hard copy image metrology. A number of workers and standards committees1 have in fact advocated such use. Increasingly, scanners are also being tasked for high spatial frequency, image microstructure metrology (which is usually reserved for high-performance microdensitometers that use microscope optics), photomultiplier tubes (PMT), and log amps. It is hard to resist their adoption for such use, given the convenience level. The high speed, large scan areas, auto-focus, discomfiting low cost, and low operator skill requirements of commercial off-the-shelf (COTS) scanners makes one question if their use for such purpose is somehow too good to be true. To confidently judge their limitations requires a comprehensive signal and noise spatial frequency performance evaluation with respect to available driver options. This paper will outline and demonstrate evaluation techniques that use existing ISO metrology standards for modulation transfer function (MTF), noise, and dynamic range with a comparison to the performance of a Photometric Data Systems (PDS) microdensitometer.

Array scanner as microdensitometer surrogate: a deal with the devil or… a great deal?

Science.gov (United States)

Williams, Donald R.

2004-10-01

Inexpensive and easy-to-use linear and area-array scanners have frequently substituted as densitometers for low-frequency (i.e., large-area) hard copy image metrology. A number of workers and standards committees1 have in fact advocated such use. Increasingly, scanners are also being tasked for high spatial frequency, image microstructure metrology (which is usually reserved for high-performance microdensitometers that use microscope optics), photomultiplier tubes (PMT), and log amps. It is hard to resist their adoption for such use, given the convenience level. The high speed, large scan areas, auto-focus, discomfiting low cost, and low operator skill requirements of commercial off-the-shelf (COTS) scanners makes one question if their use for such purpose is somehow too good to be true. To confidently judge their limitations requires a comprehensive signal and noise spatial frequency performance evaluation with respect to available driver options. This paper will outline and demonstrate evaluation techniques that use existing ISO metrology standards for modulation transfer function (MTF), noise, and dynamic range with a comparison to the performance of a Photometric Data Systems (PDS) microdensitometer.

Stabilisation of photo-multiplying gain; Stabilisation du gain des pbotomultiplicateurs

Energy Technology Data Exchange (ETDEWEB)

Tretiakoff, O; Bailly du Bois, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1956-07-01

The use of photomultiplier tubes in experimental physics is thwarted by their high responsiveness to changes in the feeding tension. Their use can be extended a great deal by a simple efficient stabilizing device which allows them to work in the same way as Geiger-Mueller tubes without losing the advantageous characteristics of photomultiplier tubes. (author) [French] L'utilisation des tubes photomultiplicateurs en physique experimentale se heurte a l'obstacle que constitue leur extreme sensibilite aux variations de la tension d'alimentation. Un systeme de stabilisation simple et efficace, permettant d'apparenter leurs caracteristiques a celles des compteurs Geiger-Muller tout en conservant les avantages propres aux tubes photomultiplicateurs, peut elargir considerablement leur domaine d'emploi. (auteur)

System for high-voltage control detectors with large number photomultipliers

International Nuclear Information System (INIS)

Donskov, S.V.; Kachanov, V.A.; Mikhajlov, Yu.V.

1985-01-01

A simple and inexpensive on-line system for hihg-voltage control which is designed for detectors with a large number of photomultipliers is developed and manufactured. It has been developed for the GAMC type hodoscopic electromagnetic calorimeters, comprising up to 4 thousand photomultipliers. High voltage variation is performed by a high-speed potentiometer which is rotated by a microengine. Block-diagrams of computer control electronics are presented. The high-voltage control system has been used for five years in the IHEP and CERN accelerator experiments. The operation experience has shown that it is quite simple and convenient in operation. In case of about 6 thousand controlled channels in both experiments no potentiometer and microengines failures were observed

Characterization of the ETEL D784UKFLB 11 in. photomultiplier tube

Energy Technology Data Exchange (ETDEWEB)

Barros, N.; Kaptanoglu, T. [University of Pennsylvania, Philadelphia, PA 19104 (United States); Kimelman, B. [Muhlenberg College, Allentown, PA 18104 (United States); Klein, J.R. [University of Pennsylvania, Philadelphia, PA 19104 (United States); Moore, E.; Nguyen, J. [University of California, Davis, Davis, CA 95616 (United States); Stavreva, K. [University of Pennsylvania, Philadelphia, PA 19104 (United States); Svoboda, R., E-mail: rsvoboda@physics.ucdavis.edu [University of California, Davis, Davis, CA 95616 (United States)

2017-04-21

Water Cherenkov and scintillator detectors are a critical tool for neutrino physics. Their large size, low threshold, and low operational cost make them excellent detectors for long baseline neutrino oscillations, proton decay, supernova and solar neutrinos, double beta decay, and ultra-high energy astrophysical neutrinos. Proposals for a new generation of large detectors rely on the availability of large format, fast, cost-effective photomultiplier tubes. The Electron Tubes Enterprises, Ltd (ETEL) D784KFLB 11 in. Photomultiplier Tube has been developed for large neutrino detectors. We have measured the timing characteristics, relative efficiency, and magnetic field sensitivity of the first fifteen prototypes.

Improvements on Fresnel arrays for high contrast imaging

Science.gov (United States)

Wilhem, Roux; Laurent, Koechlin

2018-03-01

The Fresnel Diffractive Array Imager (FDAI) is based on a new optical concept for space telescopes, developed at Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France. For the visible and near-infrared it has already proven its performances in resolution and dynamic range. We propose it now for astrophysical applications in the ultraviolet with apertures from 6 to 30 meters, aimed at imaging in UV faint astrophysical sources close to bright ones, as well as other applications requiring high dynamic range. Of course the project needs first a probatory mission at small aperture to validate the concept in space. In collaboration with institutes in Spain and Russia, we will propose to board a small prototype of Fresnel imager on the International Space Station (ISS), with a program combining technical tests and astrophysical targets. The spectral domain should contain the Lyman- α line ( λ = 121 nm). As part of its preparation, we improve the Fresnel array design for a better Point Spread Function in UV, presently on a small laboratory prototype working at 260 nm. Moreover, we plan to validate a new optical design and chromatic correction adapted to UV. In this article we present the results of numerical propagations showing the improvement in dynamic range obtained by combining and adapting three methods : central obturation, optimization of the bars mesh holding the Fresnel rings, and orthogonal apodization. We briefly present the proposed astrophysical program of a probatory mission with such UV optics.

Stability Measurements for Alignment of the NIF Neutron Imaging System Pinhole Array

International Nuclear Information System (INIS)

Fittinghoff, D.N.; Bower, D.E.; Drury, O.B.; Dzenitis, J.M.; Frank, M.; Buckles, R.A.; Munson, C.; Wilde, C.H.

2011-01-01

The alignment system for the National Ignition Facility's neutron imaging system has been commissioned and measurements of the relative stability of the 90-315 DIM, the front and the back of the neutron imaging pinhole array and an exploding pusher target have been made using the 90-135 and the 90-258 opposite port alignment systems. Additionally, a laser beam shot from the neutron-imaging Annex and reflected from a mirror at the back of the pinhole array was used to monitor the pointing of the pinhole. Over a twelve hour period, the relative stability of these parts was found to be within ∼ ±18 (micro)m rms even when using manual methods for tracking the position of the objects. For highly visible features, use of basic particle tracking techniques found that the front of the pinhole array was stable relative to the 90-135 opposite port alignment camera to within ±3.4 (micro)m rms. Reregistration, however, of the opposite port alignment systems themselves using the target alignment sensor was found to change the expected position of target chamber center by up to 194 (micro)m.

The performance of a prototype array of water Cherenkov detectors for the LHAASO project

Science.gov (United States)

An, Q.; Bai, Y. X.; Bi, X. J.; Cao, Z.; Chang, J. F.; Chen, G.; Chen, M. J.; Chen, S. M.; Chen, S. Z.; Chen, T. L.; Chen, X.; Chen, Y. T.; Cui, S. W.; Dai, B. Z.; Du, Q.; Danzengluobu; Feng, C. F.; Feng, S. H.; Gao, B.; Gao, S. Q.; Ge, M. M.; Gu, M. H.; Hao, X. J.; He, H. H.; Hou, C.; Hu, H. B.; Hu, X. B.; Huang, J.; Huang, W. P.; Jia, H. Y.; Jiang, K.; Liu, J.; Liu, J. L.; Liu, J. S.; Liu, S. B.; Liu, Y.; Liu, Y. N.; Li, Q. J.; Li, C.; Li, F.; Li, H. C.; Li, X. R.; Lu, H.; Lv, H. K.; Mao, Y. J.; Ma, L. L.; Ma, X. H.; Shao, J.; Shao, M.; Sheng, X. D.; Sun, G. X.; Sun, Z. B.; Tang, Z. B.; Wu, C. Y.; Wu, H. R.; Wu, Q.; Xiao, G.; Xu, Y.; Yang, Q. Y.; Yang, R.; Yao, Z. G.; You, X. H.; Yuan, A. F.; Zhang, B. K.; Zhang, H. M.; Zhang, S. R.; Zhang, S. S.; Zhang, X. Y.; Zhang, Y.; Zhang, L.; Zhai, L. M.; Zhao, J.; Zhao, L.; Zhao, Z. G.; Zha, M.; Zhou, B.; Zhu, F. R.; Zhu, K. J.; Zhuang, J.; Zuo, X.

2013-10-01

A large high-altitude air-shower observatory (LHAASO) is to be built at Shangri-La, Yunnan Province, China. This observatory is intended to conduct sub-TeV gamma astronomy, and as an important component of the LHAASO project, a water Cherenkov detector array (WCDA) is proposed. To investigate engineering issues and fully understand the water Cherenkov technique for detecting air showers, a prototype array at 1% scale of the LHAASO-WCDA has been built at Yang-Ba-Jing, Tibet, China. This paper introduces the prototype array setup and studies its performance by counting rate of each photomultiplier tube (PMT), trigger rates at different PMT multiplicities, and responses to air showers. Finally, the reconstructed shower directions and angular resolutions of the detected showers for the prototype array are given.

Development of portable phased array UT system for real-time flaw imaging

International Nuclear Information System (INIS)

Goto, M.

1995-01-01

Many functions and features of phased array UT technology must be useful for NDE in the industrial field. Some phased array UT systems have been developed for the inspection of nuclear pressure vessel and turbine components. However, phased array UT is still a special NDE technique and it has not been used widely in the past. The reasons of that are system size, cost, operator performance, equipment design and others. TOSHIBA has newly developed PC controlled portable phased array system to solve those problems. The portable phased array UT system is very compact and light but it is able to drive up to 32-channel linear array probe, to display real-time linear/sector B-scan, to display accumulated B-scan with an encoder and to display profile overlaid B-scan. The first applications were turbine component inspections for precise flaw investigation and flaw image data recording

Digital pulse-timing technique for the neutron detector array NEDA

Energy Technology Data Exchange (ETDEWEB)

Modamio, V., E-mail: victor.modamio@lnl.infn.it [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Valiente-Dobón, J.J. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Jaworski, G. [Faculty of Physics, Warsaw University of Technology, 00-662 Warszawa (Poland); Heavy Ion Laboratory, University of Warsaw, 02-093 Warszawa (Poland); Hüyük, T. [Instituto de Física Corpuscular, CSIC-Universitat de València, E-46980 Valencia (Spain); Triossi, A. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Egea, J. [Instituto de Física Corpuscular, CSIC-Universitat de València, E-46980 Valencia (Spain); Department of Electronic Engineering, Universitat de València, E-46100 Burjassot (Spain); Di Nitto, A. [Johannes Gutenberg-Universität Mainz, D-55099 Mainz (Germany); Söderström, P.-A. [RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, 351-0198 Saitama (Japan); Agramunt Ros, J. [Instituto de Física Corpuscular, CSIC-Universitat de València, E-46980 Valencia (Spain); Angelis, G. de [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); France, G. de [GANIL, CEA/DSAM and CNRS/IN2P3, F-14076 Caen (France); Erduran, M.N. [Faculty of Engineering and Natural Sciences, Istanbul Sabahattin Zaim University, 34303 Istanbul (Turkey); and others

2015-03-01

A new digital pulse-timing algorithm, to be used with the future neutron detector array NEDA, has been developed and tested. The time resolution of four 5 in. diameter photomultiplier tubes (XP4512, R4144, R11833-100, and ET9390-kb), coupled to a cylindrical 5 in. by 5 in. BC501A liquid scintillator detector was measured by employing digital sampling electronics and a constant fraction discriminator (CFD) algorithm. The zero crossing of the CFD algorithm was obtained with a cubic spline interpolation, which was continuous up to the second derivative. The performance of the algorithm was studied at sampling rates of 500 MS/s and 200 MS/s. The time resolution obtained with the digital electronics was compared to the values acquired with a standard analog CFD. The result of this comparison shows that the time resolution from the analog and the digital measurements at 500 MS/s and at 200 MS/s are within 15% for all the tested photomultiplier tubes.

Analysis of photon statistics with Silicon Photomultiplier

International Nuclear Information System (INIS)

D'Ascenzo, N.; Saveliev, V.; Wang, L.; Xie, Q.

2015-01-01

The Silicon Photomultiplier (SiPM) is a novel silicon-based photodetector, which represents the modern perspective of low photon flux detection. The aim of this paper is to provide an introduction on the statistical analysis methods needed to understand and estimate in quantitative way the correct features and description of the response of the SiPM to a coherent source of light

The Advanced Gamma-ray Imaging System (AGIS): A Nanosecond Time Scale Stereoscopic Array Trigger System.

Science.gov (United States)

Krennrich, Frank; Buckley, J.; Byrum, K.; Dawson, J.; Drake, G.; Horan, D.; Krawzcynski, H.; Schroedter, M.

2008-04-01

Imaging atmospheric Cherenkov telescope arrays (VERITAS, HESS) have shown unprecedented background suppression capabilities for reducing cosmic-ray induced air showers, muons and night sky background fluctuations. Next-generation arrays with on the order of 100 telescopes offer larger collection areas, provide the possibility to see the air shower from more view points on the ground, have the potential to improve the sensitivity and give additional background suppression. Here we discuss the design of a fast array trigger system that has the potential to perform a real time image analysis allowing substantially improved background rate suppression at the trigger level.

High resolution MR imaging of the hip using pelvic phased-array coil

Energy Technology Data Exchange (ETDEWEB)

Niitsu, Mamoru; Mishima, Hajime; Itai, Yuji [Tsukuba Univ., Ibaraki (Japan). Inst. of Clinical Medicine

1997-01-01

A pelvic phased-array coil was applied to obtain high resolution MR images of the hip. Three-mm-thick fast spin-echo images were obtained in seven hips. Images with a pelvic coil enhanced delineation of acetabular labrum and articular cartilage more clearly than those with a body coil or flexible-surface coil. The use of a pelvic coil in imaging of the hip may be of diagnostic value because of its superior delineation. (author)

Algorithm-structured computer arrays and networks architectures and processes for images, percepts, models, information

CERN Document Server

Uhr, Leonard

1984-01-01

Computer Science and Applied Mathematics: Algorithm-Structured Computer Arrays and Networks: Architectures and Processes for Images, Percepts, Models, Information examines the parallel-array, pipeline, and other network multi-computers.This book describes and explores arrays and networks, those built, being designed, or proposed. The problems of developing higher-level languages for systems and designing algorithm, program, data flow, and computer structure are also discussed. This text likewise describes several sequences of successively more general attempts to combine the power of arrays wi

A Parasitic Array Receiver for ISAR Imaging of Ship Targets Using a Coastal Radar

Directory of Open Access Journals (Sweden)

Fabrizio Santi

2016-01-01

Full Text Available The detection and identification of ship targets navigating in coastal areas are essential in order to prevent maritime accidents and to take countermeasures against illegal activities. Usually, coastal radar systems are employed for the detection of vessels, whereas noncooperative ship targets as well as ships not equipped with AIS transponders can be identified by means of dedicated active radar imaging system by means of ISAR processing. In this work, we define a parasitic array receiver for ISAR imaging purposes based on the signal transmitted by an opportunistic coastal radar over its successive scans. In order to obtain the proper cross-range resolution, the physical aperture provided by the array is combined with the synthetic aperture provided by the target motion. By properly designing the array of passive devices, the system is able to correctly observe the signal reflected from the ships over successive scans of the coastal radar. Specifically, the upper bounded interelement spacing provides a correct angular sampling accordingly to the Nyquist theorem and the lower bounded number of elements of the array ensures the continuity of the observation during multiple scans. An ad hoc focusing technique has been then proposed to provide the ISAR images of the ships. Simulated analysis proved the effectiveness of the proposed system to provide top-view images of ship targets suitable for ATR procedures.

Improved SPICE electrical model of silicon photomultipliers

Energy Technology Data Exchange (ETDEWEB)

Marano, D., E-mail: davide.marano@oact.inaf.it [INAF, Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy); Bonanno, G.; Belluso, M.; Billotta, S.; Grillo, A.; Garozzo, S.; Romeo, G. [INAF, Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy); Catalano, O.; La Rosa, G.; Sottile, G.; Impiombato, D.; Giarrusso, S. [INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo, Via U. La Malfa 153, I-90146 Palermo (Italy)

2013-10-21

The present work introduces an improved SPICE equivalent electrical model of silicon photomultiplier (SiPM) detectors, in order to simulate and predict their transient response to avalanche triggering events. In particular, the developed circuit model provides a careful investigation of the magnitude and timing of the read-out signals and can therefore be exploited to perform reliable circuit-level simulations. The adopted modeling approach is strictly related to the physics of each basic microcell constituting the SiPM device, and allows the avalanche timing as well as the photodiode current and voltage to be accurately simulated. Predictive capabilities of the proposed model are demonstrated by means of experimental measurements on a real SiPM detector. Simulated and measured pulses are found to be in good agreement with the expected results. -- Highlights: • An improved SPICE electrical model of silicon photomultipliers is proposed. • The developed model provides a truthful representation of the physics of the device. • An accurate charge collection as a function of the overvoltage is achieved. • The adopted electrical model allows reliable circuit-level simulations to be performed. • Predictive capabilities of the adopted model are experimentally demonstrated.

A LSO scintillator array for a PET detector module with depth of interaction measurement

International Nuclear Information System (INIS)

Huber, J.S.; Moses, W.W.; Andreaco, M.S.; Petterson, O.

2000-01-01

We present construction methods and performance results for a production scintillator array of 64 optically isolated, 3 mm x 3 mm x 30 mm sized LSO crystals. This scintillator array has been developed for a PET detector module consisting of the 8x8 LSO array coupled on one end to a single photomultiplier tube (PMT) and on the opposite end to a 64 pixel array of silicon photodiodes (PD). The PMT provides an accurate timing pulse and initial energy discrimination, the PD identifies the crystal of interaction, the sum provides a total energy signal, and the PD/(PD+PMT) ratio determines the depth of interaction (DOI). Unlike the previous LSO array prototypes, we now glue Lumirror reflector material directly onto 4 sides of each crystal to obtain an easily manufactured, mechanically rugged array with our desired depth dependence. With 511 keV excitation, we obtain a total energy signal of 3600 electrons, pulse-height resolution of 25% fwhm, and 6-15 mm fwhm DOI resolution

A new trend in photomultiplier techniques and its implications in future collider experiments

International Nuclear Information System (INIS)

Kuroda, K.

1989-01-01

A recent trend in photomultiplier techniques, characterized by immunity to magnetic fields and position sensitivity of modern photomultiplier tubes, would potentially have great importance in future collider experiments. This article presents a survey on the actual status of the art, and some implications of such new techniques in future high-energy experiments. As an example of applications, our recent project of constructing an ultrafast scintillating-fibre detector on the basis of upgraded position-sensitive PMTs is outlined. (orig.)

Microscopy refocusing and dark-field imaging by using a simple LED array

OpenAIRE

Zheng, Guoan; Kolner, Christopher; Yang, Changhuei

2011-01-01

The condenser is one of the main components in most transmitted light compound microscopes. In this Letter, we show that such a condenser can be replaced by a programmable LED array to achieve greater imaging flexibility and functionality. Without mechanically scanning the sample or changing the microscope setup, the proposed approach can be used for dark-field imaging, bright-field imaging, microscopy sectioning, and digital refocusing. Images of a starfish embryo were acquired by using such...

Demosaicing and Superresolution for Color Filter Array via Residual Image Reconstruction and Sparse Representation

OpenAIRE

Sun, Guangling

2012-01-01

A framework of demosaicing and superresolution for color filter array (CFA) via residual image reconstruction and sparse representation is presented.Given the intermediate image produced by certain demosaicing and interpolation technique, a residual image between the final reconstruction image and the intermediate image is reconstructed using sparse representation.The final reconstruction image has richer edges and details than that of the intermediate image. Specifically, a generic dictionar...

Reconstructing the CT number array from gray-level images and its application in PACS

Science.gov (United States)

Chen, Xu; Zhuang, Tian-ge; Wu, Wei

2001-08-01

Although DICOM compliant computed tomography has been prevailing in medical fields nowadays, there are some incompliant ones, from which we could hardly get the raw data and make an apropos interpretation due to the proprietary image format. Under such condition, one usually uses frame grabbers to capture CT images, the results of which could not be freely adjusted by radiologists as the original CT number array could. To alleviate the inflexibility, a new method is presented in this paper to reconstruct the array of CT number from several gray-level images acquired under different window settings. Its feasibility is investigated and a few tips are put forward to correct the errors caused respectively by 'Border Effect' and some hardware problems. The accuracy analysis proves it a good substitution for original CT number array acquisition. And this method has already been successfully used in our newly developing PACS and accepted by the radiologists in clinical use.

Hodoscope module with miniature photomultipliers

International Nuclear Information System (INIS)

Bel'zer, L.I.; Gribushin, A.M.; Zhil'tsov, L.Ya.; Matveeva, E.N.; Philipenko, T.D.; Sinev, N.B.

1987-01-01

The experimental Scintillation Magnetic Spectrometer (SMS) installation, whose main element is an extended hodoscope system, is being built for the accelerator of the High Energy Laboratory of the Joint Institute for Nuclear Research. The authors describe the scintillation hodoscope of the SMS installation and present the applicable amplitude and time characteristics of several types of miniature photomultipliers (FEU-58, FEU-60, FEU-114-1, FEU-147-1, and R-1635 (Hamamatsu, Japan)), which were obtained with a 106 Ru radioactive source and standard plastic scintillators of two types, based on oxazoles in polystyrene and in polymethylmethacrylate

Modeling crosstalk and afterpulsing in silicon photomultipliers

International Nuclear Information System (INIS)

Rosado, J.; Aranda, V.M.; Blanco, F.; Arqueros, F.

2015-01-01

An experimental method to characterize the crosstalk and afterpulsing in silicon photomultipliers has been developed and applied to two detectors fabricated by Hamamatsu. An analytical model of optical crosstalk that we presented in a previous publication has been compared with new measurements, confirming our results. Progresses on a statistical model to describe afterpulsing and delayed crosstalk are also shown and compared with preliminary experimental data

Modeling crosstalk and afterpulsing in silicon photomultipliers

Energy Technology Data Exchange (ETDEWEB)

Rosado, J., E-mail: jaime_ros@fis.ucm.es; Aranda, V.M.; Blanco, F.; Arqueros, F.

2015-07-01

An experimental method to characterize the crosstalk and afterpulsing in silicon photomultipliers has been developed and applied to two detectors fabricated by Hamamatsu. An analytical model of optical crosstalk that we presented in a previous publication has been compared with new measurements, confirming our results. Progresses on a statistical model to describe afterpulsing and delayed crosstalk are also shown and compared with preliminary experimental data.

The performance of a prototype array of water Cherenkov detectors for the LHAASO project

Energy Technology Data Exchange (ETDEWEB)

An, Q. [University of Science and Technology of China, Hefei 230026 (China); State Key Laboratory of Particle Detection and Electronics, Beijing 100049 (China); Bai, Y.X.; Bi, X.J.; Cao, Z. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Chang, J.F. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics, Beijing 100049 (China); Chen, G.; Chen, M.J. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Chen, S.M. [Tsinghua University, Beijing 100084 (China); Chen, S.Z. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Chen, T.L. [University of Tibet, Lhasa 851600 (China); Chen, X. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Chen, Y.T. [University of Yunnan, Kunming 650091 (China); Cui, S.W. [Normal University of Hebei, Shijiazhuang 050016 (China); Dai, B.Z. [University of Yunnan, Kunming 650091 (China); Du, Q. [Tsinghua University, Beijing 100084 (China); Danzengluobu [University of Tibet, Lhasa 851600 (China); Feng, C.F. [University of Shandong, Jinan 250100 (China); Feng, S.H.; Gao, B. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Gao, S.Q. [National Space Science Center, Chinese Academy of Sciences, Beijing 100190 (China); and others

2013-10-01

A large high-altitude air-shower observatory (LHAASO) is to be built at Shangri-La, Yunnan Province, China. This observatory is intended to conduct sub-TeV gamma astronomy, and as an important component of the LHAASO project, a water Cherenkov detector array (WCDA) is proposed. To investigate engineering issues and fully understand the water Cherenkov technique for detecting air showers, a prototype array at 1% scale of the LHAASO-WCDA has been built at Yang-Ba-Jing, Tibet, China. This paper introduces the prototype array setup and studies its performance by counting rate of each photomultiplier tube (PMT), trigger rates at different PMT multiplicities, and responses to air showers. Finally, the reconstructed shower directions and angular resolutions of the detected showers for the prototype array are given. -- Highlights: • The technique of the water Cherenkov array is studied. • Engineering issues of the water Cherenkov array are investigated. • The PMTs and electronics of the water Cherenkov array are tested. • Some key parameters of the water Cherenkov array are measured.

The performance of a prototype array of water Cherenkov detectors for the LHAASO project

International Nuclear Information System (INIS)

An, Q.; Bai, Y.X.; Bi, X.J.; Cao, Z.; Chang, J.F.; Chen, G.; Chen, M.J.; Chen, S.M.; Chen, S.Z.; Chen, T.L.; Chen, X.; Chen, Y.T.; Cui, S.W.; Dai, B.Z.; Du, Q.; Danzengluobu; Feng, C.F.; Feng, S.H.; Gao, B.; Gao, S.Q.

2013-01-01

A large high-altitude air-shower observatory (LHAASO) is to be built at Shangri-La, Yunnan Province, China. This observatory is intended to conduct sub-TeV gamma astronomy, and as an important component of the LHAASO project, a water Cherenkov detector array (WCDA) is proposed. To investigate engineering issues and fully understand the water Cherenkov technique for detecting air showers, a prototype array at 1% scale of the LHAASO-WCDA has been built at Yang-Ba-Jing, Tibet, China. This paper introduces the prototype array setup and studies its performance by counting rate of each photomultiplier tube (PMT), trigger rates at different PMT multiplicities, and responses to air showers. Finally, the reconstructed shower directions and angular resolutions of the detected showers for the prototype array are given. -- Highlights: • The technique of the water Cherenkov array is studied. • Engineering issues of the water Cherenkov array are investigated. • The PMTs and electronics of the water Cherenkov array are tested. • Some key parameters of the water Cherenkov array are measured

High-Resolution Spin-on-Patterning of Perovskite Thin Films for a Multiplexed Image Sensor Array.

Science.gov (United States)

Lee, Woongchan; Lee, Jongha; Yun, Huiwon; Kim, Joonsoo; Park, Jinhong; Choi, Changsoon; Kim, Dong Chan; Seo, Hyunseon; Lee, Hakyong; Yu, Ji Woong; Lee, Won Bo; Kim, Dae-Hyeong

2017-10-01

Inorganic-organic hybrid perovskite thin films have attracted significant attention as an alternative to silicon in photon-absorbing devices mainly because of their superb optoelectronic properties. However, high-definition patterning of perovskite thin films, which is important for fabrication of the image sensor array, is hardly accomplished owing to their extreme instability in general photolithographic solvents. Here, a novel patterning process for perovskite thin films is described: the high-resolution spin-on-patterning (SoP) process. This fast and facile process is compatible with a variety of spin-coated perovskite materials and perovskite deposition techniques. The SoP process is successfully applied to develop a high-performance, ultrathin, and deformable perovskite-on-silicon multiplexed image sensor array, paving the road toward next-generation image sensor arrays. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photomultipliers gain monitoring at the one percent level with a blue light pulser

International Nuclear Information System (INIS)

Berger, J.; Bermond, M.; Besson, P.; Favier, J.; Pessard, H.; Poulet, M.

1988-07-01

We describe a method and an experimental layout allowing the monitoring of photomultipliers gain. We use artificial blue light (Spark-gap with filter: 436 ± 20 nm) and three reference detectors. Short term and long term measurements are presented. The results indicate a precision better than 0.5% for the short term and 1.4% for the long term determinations. This gain monitoring system has been developed for a new neutrino oscillation reactor experiment (600 photomultipliers) starting at the Bugey nuclear plant

Development of gaseous photomultiplier

International Nuclear Information System (INIS)

Tokanai, F.; Sumiyoshi, T.; Sugiyama, H.; Okada, T.

2014-01-01

We have been developing gaseous photomultiplier tubes (PMTs) with alkali photocathode combined with micropattern gas detectors (MPGDs). The potential advantage of the gaseous PMT is that it can achieve a very large effective area with adequate position and timing resolutions. In addition, it will be easily operated under a very high magnetic field, compared with the conventional vacuum-based PMT. To evaluate the gaseous PMTs filled with Ne and Ar based gas mixture, we have developed gaseous PMTs with an alkali photocathode combined with MPGDs such as a glass capillary plate, GEM, and Micromegas detector. We describe the recent development of the gaseous PMTs, particularly the production of the photocathode, gas gain, ion and photon feedbacks, quantum efficiency, and the characteristics in the magnetic field environment. (author)

Immersion cooling of silicon photomultipliers (SiPM) for nuclear medicine imaging applications

International Nuclear Information System (INIS)

Raylman, R.R.; Stolin, A.V.

2016-01-01

Silicon photomultipliers (SiPM) are compact, high amplification light detection devices that have recently been incorporated into magnetic field-compatible positron emission tomography (PET) scanners. To take full advantage of these devices, it is preferable to cool them below room temperature. Most current methods are limited to the cooling of individual detector modules, increasing complexity and cost of scanners made-up of a large number of modules. In this work we investigated a new method of cooling, immersion of the detector modules in non-electrically conductive, cooled liquid. A small-scale prototype system was constructed to cool a relatively large area SiPM-based, scintillator detector module by immersing it in a circulating bath of mineral oil. Testing demonstrated that the system rapidly decreased and stabilized the temperature of the device. Operation of the detector illustrated the expected benefits of cooling, with no apparent degradation of performance attributable to immersion in fluid. - Highlights: • Immersion cooling is new, simple and inexpensive method to cool solid state based nuclear medicine scanner. • Method successfully tested on a scaled version of an SiPM-based PET detector module. • Can be scaled up to cool a complete PET scanner.

The ASTRI mini-array within the future Cherenkov Telescope Array

Directory of Open Access Journals (Sweden)

Vercellone Stefano

2016-01-01

Full Text Available The Cherenkov Telescope Array (CTA is a large collaborative effort aimed at the design and operation of an observatory dedicated to very high-energy gamma-ray astrophysics in the energy range from a few tens of GeV to above 100 TeV, which will yield about an order of magnitude improvement in sensitivity with respect to the current major arrays (H.E.S.S., MAGIC, and VERITAS. Within this framework, the Italian National Institute for Astrophysics is leading the ASTRI project, whose main goals are the design and installation on Mt. Etna (Sicily of an end-to-end dual-mirror prototype of the CTA small size telescope (SST and the installation at the CTA Southern site of a dual-mirror SST mini-array composed of nine units with a relative distance of about 300 m. The innovative dual-mirror Schwarzschild-Couder optical solution adopted for the ASTRI Project allows us to substantially reduce the telescope plate-scale and, therefore, to adopt silicon photo-multipliers as light detectors. The ASTRI mini-array is a wider international effort. The mini-array, sensitive in the energy range 1–100 TeV and beyond with an angular resolution of a few arcmin and an energy resolution of about 10–15%, is well suited to study relatively bright sources (a few × 10−12 erg cm−2 s−1 at 10 TeV at very high energy. Prominent sources such as extreme blazars, nearby well-known BL Lac objects, Galactic pulsar wind nebulae, supernovae remnants, micro-quasars, and the Galactic Center can be observed in a previously unexplored energy range. The ASTRI mini-array will extend the current IACTs sensitivity well above a few tens of TeV and, at the same time, will allow us to compare our results on a few selected targets with those of current (HAWC and future high-altitude extensive air-shower detectors.

Radio Observations of the Ionosphere From an Imaging Array and a CubeSat

Science.gov (United States)

Isham, B.; Gustavsson, B.; Bullett, T. W.; Bergman, J. E. S.; Rincón-Charris, A.; Bruhn, F.; Funk, P.

2017-12-01

The ionosphere is a source of many radio emissions in the various low-frequency, medium-frequency, and high-frequency bands (0 to 30 MHz). In addition to natural radio emissions, artificial emissions can be stimulated using high-power radiowave ionospheric modification facilities. Two complementary projects are underway for the purpose of improving our knowledge of the processes of radio emissions from the ionosphere. One project is the Aguadilla radio array, located in northwestern Puerto Rico. The Aguadilla array is intended to produce 2 to 25 MHz radio images of the ionosphere, as well as to perform bistatic radar imaging of the ionosphere over Puerto Rico. The array will consist of multiple antenna elements, each of which is a single active (electromagnetically short) crossed electric dipole. The elements are arranged within a roughly 200 by 300-meter core array, in a semi-random pattern providing an optimal distribution of baseline vectors, with 6-meter minimum spacing to eliminate spacial aliasing. In addition, several elements are arranged in a partial ring around the central core, providing a roughly four times expanded region in u-v space for improved image resolution and quality. Phase is maintained via cabled connections to a central location. A remote array is also being developed, in which phase is maintained between elements by through the use of GPS-disciplined rubidium clocks. The other project involves the GimmeRF radio instrument, designed for 0.3 to 30 MHz vector observation of the radio electric field, and planned for launch in 2020 on a CubeSat. The data rate that can be sustained by GimmeRF far exceeds any available communication strategy. By exploiting fast on-board computing and efficient artificial intelligence (AI) algorithms for analysis and data selection, the usage of the telemetry link can be optimized and value added to the mission. Radio images recorded by the radio array from below the ionosphere can be directly compared with the

Infrared Imaging of Cotton Fiber Bundles Using a Focal Plane Array Detector and a Single Reflectance Accessory

Directory of Open Access Journals (Sweden)

Michael Santiago Cintrón

2016-11-01

Full Text Available Infrared imaging is gaining attention as a technique used in the examination of cotton fibers. This type of imaging combines spectral analysis with spatial resolution to create visual images that examine sample composition and distribution. Herein, we report on the use of an infrared instrument equipped with a reflection accessory and an array detector system for the examination of cotton fiber bundles. Cotton vibrational spectra and chemical images were acquired by grouping pixels in the detector array. This technique reduced spectral noise and was employed to visualize cell wall development in cotton fibers bundles. Fourier transform infrared spectra reveal band changes in the C–O bending region that matched previous studies. Imaging studies were quick, relied on small amounts of sample and provided a distribution of the cotton fiber cell wall composition. Thus, imaging of cotton bundles with an infrared detector array has potential for use in cotton fiber examinations.

Depth extraction method with high accuracy in integral imaging based on moving array lenslet technique

Science.gov (United States)

Wang, Yao-yao; Zhang, Juan; Zhao, Xue-wei; Song, Li-pei; Zhang, Bo; Zhao, Xing

2018-03-01

In order to improve depth extraction accuracy, a method using moving array lenslet technique (MALT) in pickup stage is proposed, which can decrease the depth interval caused by pixelation. In this method, the lenslet array is moved along the horizontal and vertical directions simultaneously for N times in a pitch to get N sets of elemental images. Computational integral imaging reconstruction method for MALT is taken to obtain the slice images of the 3D scene, and the sum modulus (SMD) blur metric is taken on these slice images to achieve the depth information of the 3D scene. Simulation and optical experiments are carried out to verify the feasibility of this method.

Transition-edge sensor imaging arrays for astrophysics applications

Science.gov (United States)

Burney, Jennifer Anne

Many interesting objects in our universe currently elude observation in the optical band: they are too faint or they vary rapidly and thus any structure in their radiation is lost over the period of an exposure. Conventional photon detectors cannot simultaneously provide energy resolution and time-stamping of individual photons at fast rates. Superconducting detectors have recently made the possibility of simultaneous photon counting, imaging, and energy resolution a reality. Our research group has pioneered the use of one such detector, the Transition-Edge Sensor (TES). TES physics is simple and elegant. A thin superconducting film, biased at its critical temperature, can act as a particle detector: an incident particle deposits energy and drives the film into its superconducting-normal transition. By inductively coupling the detector to a SQUID amplifier circuit, this resistance change can be read out as a current pulse, and its energy deduced by integrating over the pulse. TESs can be used to accurately time-stamp (to 0.1 [mu]s) and energy-resolve (0.15 eV at 1.6 eV) near-IR/visible/near-UV photons at rates of 30~kHz. The first astronomical observations using fiber-coupled detectors were made at the Stanford Student Observatory 0.6~m telescope in 1999. Further observations of the Crab Pulsar from the 107" telescope at the University of Texas McDonald Observatory showed rapid phase variations over the near-IR/visible/near-UV band. These preliminary observations provided a glimpse into a new realm of observations of pulsars, binary systems, and accreting black holes promised by TES arrays. This thesis describes the development, characterization, and preliminary use of the first camera system based on Transition-Edge Sensors. While single-device operation is relatively well-understood, the operation of a full imaging array poses significant challenges. This thesis addresses all aspects related to the creation and characterization of this cryogenic imaging

'Optical' soft x-ray arrays for fluctuation diagnostics in magnetic fusion energy experiments

International Nuclear Information System (INIS)

Delgado-Aparicio, L.F.; Stutman, D.; Tritz, K.; Finkenthal, M.; Kaita, R.; Roquemore, L.; Johnson, D.; Majeski, R.

2004-01-01

We are developing large pixel count, fast (≥100 kHz) and continuously sampling soft x-ray (SXR) array for the diagnosis of magnetohydrodynamics (MHD) and turbulent fluctuations in magnetic fusion energy plasmas. The arrays are based on efficient scintillators, high thoughput multiclad fiber optics, and multichannel light amplification and integration. Compared to conventional x-ray diode arrays, such systems can provide vastly increased spatial coverage, and access to difficult locations with small neutron noise and damage. An eight-channel array has been built using columnar CsI:Tl as an SXR converter and a multianode photomultiplier tube as photoamplifier. The overall system efficiency is measured using laboratory SXR sources, while the time response and signal-to-noise performance have been evaluated by recording MHD activity from the spherical tori (ST) Current Drive Experiment-Upgrade and National Spherical Torus Experiment, both at Princeton Plasma Physics Laboratory

Sampling phased array - a new technique for ultrasonic signal processing and imaging

OpenAIRE

Verkooijen, J.; Boulavinov, A.

2008-01-01

Over the past 10 years, the improvement in the field of microelectronics and computer engineering has led to significant advances in ultrasonic signal processing and image construction techniques that are currently being applied to non-destructive material evaluation. A new phased array technique, called 'Sampling Phased Array', has been developed in the Fraunhofer Institute for Non-Destructive Testing([1]). It realises a unique approach of measurement and processing of ultrasonic signals. Th...

Characterization of 1600 Hamamatsu 16-anode photomultipliers for the MINOS Far detector

International Nuclear Information System (INIS)

Lang, K.; Day, J.; Eilerts, S.; Fuqua, S.; Guillen, A.; Kordosky, M.; Lang, M.; Liu, J.; Opaska, W.; Proga, M.; Vahle, P.; Winbow, A.; Drake, G.; Thomas, J.; Andreopoulos, C.; Saoulidou, N.; Stamoulis, P.; Tzanakos, G.; Zois, M.; Weber, A.; Michael, D.

2005-01-01

We are reporting results of the characterization of over 1600 multi-anode R5900-00-M16 photomultipliers manufactured by Hamamatsu Photonics K.K., and installed in the MINOS Far detector. We have conducted extensive tests of the uniformity of gain and collection efficiency of individual anodes, the cross-talk among all 16 channels, the dark noise, and the linearity of response. In our studies we used a blue light-emitting diode to illuminate phototubes through 1.2 mm diameter optical fibers. In this paper, we present summaries of the main characteristics of the tested photomultipliers

Numerical Study of a Crossed Loop Coil Array for Parallel Magnetic Resonance Imaging

International Nuclear Information System (INIS)

Hernandez, J.; Solis, S. E.; Rodriguez, A. O.

2008-01-01

A coil design has been recently proposed by Temnikov (Instrum Exp Tech. 2005;48;636-637), with higher experimental signal-to-noise ratio than that of the birdcage coil. It is also claimed that it is possible to individually tune it with a single chip capacitor. This coil design shows a great resemble to the gradiometer coil. These results motivated us to numerically simulate a three-coil array for parallel magnetic resonance imaging and in vivo magnetic resonance spectroscopy with multi nuclear capability. The magnetic field was numerical simulated by solving Maxwell's equations with the finite element method. Uniformity profiles were calculated at the midsection for one single coil and showed a good agreement with the experimental data. Then, two more coils were added to form two different coil arrays: coil elements were equally distributed by an angle of a 30 deg. angle. Then, uniformity profiles were calculated again for all cases at the midsection. Despite the strong interaction among all coil elements, very good field uniformity can be achieved. These numerical results indicate that this coil array may be a good choice for magnetic resonance imaging parallel imaging

Development of a SiPM-based PET imaging system for small animals

International Nuclear Information System (INIS)

Lu, Yanye; Yang, Kun; Zhou, Kedi; Zhang, Qiushi; Pang, Bo; Ren, Qiushi

2014-01-01

Advances in small animal positron emission tomography (PET) imaging have been accelerated by many new technologies such as the successful incorporation of silicon photomultiplier (SiPM). In this paper, we have developed a compact, lightweight PET imaging system that is based on SiPM detectors for small animals imaging, which could be integrated into a multi-modality imaging system. This PET imaging system consists of a stationary detector gantry, a motor-controlled animal bed module, electronics modules, and power supply modules. The PET detector, which was designed as a multi-slice circular ring geometry of 27 discrete block detectors, is composed of a cerium doped lutetium–yttrium oxyorthosilicate (LYSO) scintillation crystal and SiPM arrays. The system has a 60 mm transaxial field of view (FOV) and a 26 mm axial FOV. Performance tests (e.g. spatial resolution, energy resolution, and sensitivity) and phantom and animal imaging studies were performed to evaluate the imaging performance of the PET imaging system. The performance tests and animal imaging results demonstrate the feasibility of an animal PET system based on SiPM detectors and indicate that SiPM detectors can be promising photodetectors in animal PET instrumentation development

Development of a SiPM-based PET imaging system for small animals

Energy Technology Data Exchange (ETDEWEB)

Lu, Yanye [Department of Biomedicine and Engineering, College of Engineering, Peking University, Beijing 100871 (China); Yang, Kun, E-mail: yangkun9999@hotmail.com [Department of Control Technology and Instrumentation, College of Quality and Technical Supervision, Hebei University, Baoding, 071000 (China); Zhou, Kedi; Zhang, Qiushi; Pang, Bo [Department of Biomedicine and Engineering, College of Engineering, Peking University, Beijing 100871 (China); Ren, Qiushi, E-mail: renqsh@coe.pku.edu.cn [Department of Biomedicine and Engineering, College of Engineering, Peking University, Beijing 100871 (China)

2014-04-11

Advances in small animal positron emission tomography (PET) imaging have been accelerated by many new technologies such as the successful incorporation of silicon photomultiplier (SiPM). In this paper, we have developed a compact, lightweight PET imaging system that is based on SiPM detectors for small animals imaging, which could be integrated into a multi-modality imaging system. This PET imaging system consists of a stationary detector gantry, a motor-controlled animal bed module, electronics modules, and power supply modules. The PET detector, which was designed as a multi-slice circular ring geometry of 27 discrete block detectors, is composed of a cerium doped lutetium–yttrium oxyorthosilicate (LYSO) scintillation crystal and SiPM arrays. The system has a 60 mm transaxial field of view (FOV) and a 26 mm axial FOV. Performance tests (e.g. spatial resolution, energy resolution, and sensitivity) and phantom and animal imaging studies were performed to evaluate the imaging performance of the PET imaging system. The performance tests and animal imaging results demonstrate the feasibility of an animal PET system based on SiPM detectors and indicate that SiPM detectors can be promising photodetectors in animal PET instrumentation development.

Influence of incident light wavelength on time jitter of fast photomultipliers

International Nuclear Information System (INIS)

Moszynski, M.; Vacher, J.

1977-01-01

The study of the single photoelectron time resolution as a function of the wavelength of the incident light was performed for a 56 CVP photomultiplier having an S-1 photocathode. The light flash from the XP22 light emitting diode generator was passed through passband filters and illuminated the 5 mm diameter central part of the photocathode. A significant increase of the time resolution above 30% was observed when the wavelength of the incident light was changed from 790 nm to 580 nm. This gives experimental evidence that the time jitter resulting from the spread of the initial velocity of photoelectrons is proportional to the square root of the maximal initial energy of photoelectrons. Based on this conclusion the measured time jitter of C31024, RCA8850 and XP2020 photomultipliers with the use of the XP22 light emitting diode at 560 nm light wavelength was recalculated to estimate the time jitter at 400 nm near the maximum of the photocathode sensitivity. It shows an almost twice larger time spread at 400 nm for the C31024 and RCA8850 with a high gain first dynode and an about 1.5 times larger time spread for the XP2020 photomultiplier, than those measured at 560 nm. (Auth.)

A CMOS ASIC Design for SiPM Arrays.

Science.gov (United States)

Dey, Samrat; Banks, Lushon; Chen, Shaw-Pin; Xu, Wenbin; Lewellen, Thomas K; Miyaoka, Robert S; Rudell, Jacques C

2011-12-01

Our lab has previously reported on novel board-level readout electronics for an 8×8 silicon photomultiplier (SiPM) array featuring row/column summation technique to reduce the hardware requirements for signal processing. We are taking the next step by implementing a monolithic CMOS chip which is based on the row-column architecture. In addition, this paper explores the option of using diagonal summation as well as calibration to compensate for temperature and process variations. Further description of a timing pickoff signal which aligns all of the positioning (spatial channels) pulses in the array is described. The ASIC design is targeted to be scalable with the detector size and flexible to accommodate detectors from different vendors. This paper focuses on circuit implementation issues associated with the design of the ASIC to interface our Phase II MiCES FPGA board with a SiPM array. Moreover, a discussion is provided for strategies to eventually integrate all the analog and mixed-signal electronics with the SiPM, on either a single-silicon substrate or multi-chip module (MCM).

Multi-viewpoint Image Array Virtual Viewpoint Rapid Generation Algorithm Based on Image Layering

Science.gov (United States)

Jiang, Lu; Piao, Yan

2018-04-01

The use of multi-view image array combined with virtual viewpoint generation technology to record 3D scene information in large scenes has become one of the key technologies for the development of integrated imaging. This paper presents a virtual viewpoint rendering method based on image layering algorithm. Firstly, the depth information of reference viewpoint image is quickly obtained. During this process, SAD is chosen as the similarity measure function. Then layer the reference image and calculate the parallax based on the depth information. Through the relative distance between the virtual viewpoint and the reference viewpoint, the image layers are weighted and panned. Finally the virtual viewpoint image is rendered layer by layer according to the distance between the image layers and the viewer. This method avoids the disadvantages of the algorithm DIBR, such as high-precision requirements of depth map and complex mapping operations. Experiments show that, this algorithm can achieve the synthesis of virtual viewpoints in any position within 2×2 viewpoints range, and the rendering speed is also very impressive. The average result proved that this method can get satisfactory image quality. The average SSIM value of the results relative to real viewpoint images can reaches 0.9525, the PSNR value can reaches 38.353 and the image histogram similarity can reaches 93.77%.

Image-guided ultrasound phased arrays are a disruptive technology for non-invasive therapy.

Science.gov (United States)

Hynynen, Kullervo; Jones, Ryan M

2016-09-07

Focused ultrasound offers a non-invasive way of depositing acoustic energy deep into the body, which can be harnessed for a broad spectrum of therapeutic purposes, including tissue ablation, the targeting of therapeutic agents, and stem cell delivery. Phased array transducers enable electronic control over the beam geometry and direction, and can be tailored to provide optimal energy deposition patterns for a given therapeutic application. Their use in combination with modern medical imaging for therapy guidance allows precise targeting, online monitoring, and post-treatment evaluation of the ultrasound-mediated bioeffects. In the past there have been some technical obstacles hindering the construction of large aperture, high-power, densely-populated phased arrays and, as a result, they have not been fully exploited for therapy delivery to date. However, recent research has made the construction of such arrays feasible, and it is expected that their continued development will both greatly improve the safety and efficacy of existing ultrasound therapies as well as enable treatments that are not currently possible with existing technology. This review will summarize the basic principles, current statures, and future potential of image-guided ultrasound phased arrays for therapy.

Towards Optical Partial Discharge Detection with Micro Silicon Photomultipliers

Directory of Open Access Journals (Sweden)

Ming Ren

2017-11-01

Full Text Available Optical detection is reliable in intrinsically characterizing partial discharges (PDs. Because of the great volume and high-level power supply of the optical devices that can satisfy the requirements in photosensitivity, optical PD detection can merely be used in laboratory studies. To promote the practical application of the optical approach in an actual power apparatus, a silicon photomultiplier (SiPM-based PD sensor is introduced in this paper, and its basic properties, which include the sensitivity, pulse resolution, correlation with PD severity, and electromagnetic (EM interference immunity, are experimentally evaluated. The stochastic phase-resolved PD pattern (PRPD for three typical insulation defects are obtained by SiPM PD detector and are compared with those obtained using a high-frequency current transformer (HFCT and a vacuum photomultiplier tube (PMT. Because of its good performances in the above aspects and its additional advantages, such as the small size, low power supply, and low cost, SiPM offers great potential in practical optical PD monitoring.

Multisite two-photon imaging of neurons on multielectrode arrays

Science.gov (United States)

Potter, Steve M.; Lukina, Natalia; Longmuir, Kenneth J.; Wu, Yan

2001-04-01

We wish to understand how neural systems store, recall, and process information. We are using cultured networks of cortical neurons grown on microelectrode arrays as a model system for studying the emergent properties of ensembles of living neurons. We have developed a 2-way communication interface between the cultured network and a computer- generated animal, the Neurally Controlled Animat. Neural activity is used to control the behavior of the Animat, and 2- photon time-lapse imaging is carried out in order to observe the morphological changes that might underlie changes in neural processing. The 2-photon microscope is ideal for repeated imaging over hours or days, with submicron resolution and little photodamage. We have designed a computer-controlled microscope stage that allows imaging several locations in sequence, in order to collect more image data. For the latest progress, see: http://www.caltech.edu/~pinelab/PotterGroup.htm.

Performance studies of varian VPM-154D.6D VPM-154A/1.6L static crossed field photomultipliers

International Nuclear Information System (INIS)

Lo, C.C.; Leskovar, B.

1977-01-01

Characteristics have been measured for the Varian VPM-154D.6D and VPM-154A/1.6L Static Crossed Field Photomultipliers. Some typical photomultiplier characteristics such as: gain, dark current, quantum efficiency, and rise-time--are compared with data provided by the manufacturer. Photomultiplier characteristics generally not available from the manufacturer, such as: transit time, FWHM of the output pulse, peak output current measurement and multiphotoelectron time resolution were measured and are discussed

High-Resolution Imaging System (HiRIS) based on H9500 PSPMT

International Nuclear Information System (INIS)

Trotta, C.; Massari, R.; Trinci, G.; Palermo, N.; Boccalini, S.; Scopinaro, F.; Soluri, A.

2008-01-01

The H8500 PhotoMultiplier Tube (PMT) from Hamamatsu has been used in the last years to assemble several scintigraphic devices in order to achieve high-resolution gamma cameras. If the detector is coupled to discrete scintillator with millimetric pixel size, the resulting charge distribution that emerges is not properly sampled by its anodes (6x6 mm 2 ). The new position sensitive PMT H9500, with its 3x3 mm 2 anodes, allows a better charge distribution sampling, improving both spatial resolution and linearity of the system. In this paper, we investigate the imaging performances of the H9500 PMT coupled with a CsI(Tl) array having 1 mm pixel size and compare the results with the same scintillator coupled with H8500 PMT. A portable imaging system named HiRIS (High-Resolution Imaging System) was then realized using a miniaturized readout electronic. Thanks to its lightness, it can be easily used in Medical Imaging. We used HiRIS, together with a rotating system, to carry out a tomographic reconstruction of the biodistribution of a radiopharmaceutical in rats

Performance of a high-resolution depth-encoding PET detector module using linearly-graded SiPM arrays

Science.gov (United States)

Du, Junwei; Bai, Xiaowei; Gola, Alberto; Acerbi, Fabio; Ferri, Alessandro; Piemonte, Claudio; Yang, Yongfeng; Cherry, Simon R.

2018-02-01

The goal of this study was to exploit the excellent spatial resolution characteristics of a position-sensitive silicon photomultiplier (SiPM) and develop a high-resolution depth-of-interaction (DOI) encoding positron emission tomography (PET) detector module. The detector consists of a 30  ×  30 array of 0.445  ×  0.445  ×  20 mm3 polished LYSO crystals coupled to two 15.5  ×  15.5 mm2 linearly-graded SiPM (LG-SiPM) arrays at both ends. The flood histograms show that all the crystals in the LYSO array can be resolved. The energy resolution, the coincidence timing resolution and the DOI resolution were 21.8  ±  5.8%, 1.23  ±  0.10 ns and 3.8  ±  1.2 mm, respectively, at a temperature of -10 °C and a bias voltage of 35.0 V. The performance did not degrade significantly for event rates of up to 130 000 counts s-1. This detector represents an attractive option for small-bore PET scanner designs that simultaneously emphasize high spatial resolution and high detection efficiency, important, for example, in preclinical imaging of the rodent brain with neuroreceptor ligands.

Curvilinear 3-D Imaging Using Row--Column-Addressed 2-D Arrays with a Diverging Lens: Feasibility Study

DEFF Research Database (Denmark)

Bouzari, Hamed; Engholm, Mathias; Beers, Christopher

2017-01-01

imaging. Extended FOV and low channel count of double-curved RCA 2-D arrays make 3-D imaging possible with equipment in the price range of conventional 2-D imaging. This study proposes a delay-and-sum beamformation scheme specific to double-curved RCA 2-D arrays and validates its focusing ability based...... of this study demonstrate that the proposed beamforming approach is accurate for achieving correct time-of-flight calculations, and hence avoids geometrical distortions....

Batch production of microchannel plate photo-multipliers

Energy Technology Data Exchange (ETDEWEB)

Frisch, Henry J.; Wetstein, Matthew; Elagin, Andrey

2018-03-06

In-situ methods for the batch fabrication of flat-panel micro-channel plate (MCP) photomultiplier tube (PMT) detectors (MCP-PMTs), without transporting either the window or the detector assembly inside a vacuum vessel are provided. The method allows for the synthesis of a reflection-mode photocathode on the entrance to the pores of a first MCP or the synthesis of a transmission-mode photocathode on the vacuum side of a photodetector entrance window.

An integrated circuit with transmit beamforming flip-chip bonded to a 2-D CMUT array for 3-D ultrasound imaging.

Science.gov (United States)

Wygant, Ira O; Jamal, Nafis S; Lee, Hyunjoo J; Nikoozadeh, Amin; Oralkan, Omer; Karaman, Mustafa; Khuri-Yakub, Butrus T

2009-10-01

State-of-the-art 3-D medical ultrasound imaging requires transmitting and receiving ultrasound using a 2-D array of ultrasound transducers with hundreds or thousands of elements. A tight combination of the transducer array with integrated circuitry eliminates bulky cables connecting the elements of the transducer array to a separate system of electronics. Furthermore, preamplifiers located close to the array can lead to improved receive sensitivity. A combined IC and transducer array can lead to a portable, high-performance, and inexpensive 3-D ultrasound imaging system. This paper presents an IC flip-chip bonded to a 16 x 16-element capacitive micromachined ultrasonic transducer (CMUT) array for 3-D ultrasound imaging. The IC includes a transmit beamformer that generates 25-V unipolar pulses with programmable focusing delays to 224 of the 256 transducer elements. One-shot circuits allow adjustment of the pulse widths for different ultrasound transducer center frequencies. For receiving reflected ultrasound signals, the IC uses the 32-elements along the array diagonals. The IC provides each receiving element with a low-noise 25-MHz-bandwidth transimpedance amplifier. Using a field-programmable gate array (FPGA) clocked at 100 MHz to operate the IC, the IC generated properly timed transmit pulses with 5-ns accuracy. With the IC flip-chip bonded to a CMUT array, we show that the IC can produce steered and focused ultrasound beams. We present 2-D and 3-D images of a wire phantom and 2-D orthogonal cross-sectional images (Bscans) of a latex heart phantom.

A comparison of earthquake backprojection imaging methods for dense local arrays

Science.gov (United States)

Beskardes, G. D.; Hole, J. A.; Wang, K.; Michaelides, M.; Wu, Q.; Chapman, M. C.; Davenport, K. K.; Brown, L. D.; Quiros, D. A.

2018-03-01

Backprojection imaging has recently become a practical method for local earthquake detection and location due to the deployment of densely sampled, continuously recorded, local seismograph arrays. While backprojection sometimes utilizes the full seismic waveform, the waveforms are often pre-processed and simplified to overcome imaging challenges. Real data issues include aliased station spacing, inadequate array aperture, inaccurate velocity model, low signal-to-noise ratio, large noise bursts and varying waveform polarity. We compare the performance of backprojection with four previously used data pre-processing methods: raw waveform, envelope, short-term averaging/long-term averaging and kurtosis. Our primary goal is to detect and locate events smaller than noise by stacking prior to detection to improve the signal-to-noise ratio. The objective is to identify an optimized strategy for automated imaging that is robust in the presence of real-data issues, has the lowest signal-to-noise thresholds for detection and for location, has the best spatial resolution of the source images, preserves magnitude, and considers computational cost. Imaging method performance is assessed using a real aftershock data set recorded by the dense AIDA array following the 2011 Virginia earthquake. Our comparisons show that raw-waveform backprojection provides the best spatial resolution, preserves magnitude and boosts signal to detect events smaller than noise, but is most sensitive to velocity error, polarity error and noise bursts. On the other hand, the other methods avoid polarity error and reduce sensitivity to velocity error, but sacrifice spatial resolution and cannot effectively reduce noise by stacking. Of these, only kurtosis is insensitive to large noise bursts while being as efficient as the raw-waveform method to lower the detection threshold; however, it does not preserve the magnitude information. For automatic detection and location of events in a large data set, we

Cardiac cine imaging at 3 Tesla: initial experience with a 32-element body-array coil.

Science.gov (United States)

Fenchel, Michael; Deshpande, Vibhas S; Nael, Kambiz; Finn, J Paul; Miller, Stephan; Ruehm, Stefan; Laub, Gerhard

2006-08-01

We sought to assess the feasibility of cardiac cine imaging and evaluate image quality at 3 T using a body-array coil with 32 coil elements. Eight healthy volunteers (3 men; median age 29 years) were examined on a 3-T magnetic resonance scanner (Magnetom Trio, Siemens Medical Solutions) using a 32-element phased-array coil (prototype from In vivo Corp.). Gradient-recalled-echo (GRE) cine (GRAPPAx3), GRE cine with tagging lines, steady-state-free-precession (SSFP) cine (GRAPPAx3 and x4), and SSFP cine(TSENSEx4 andx6) images were acquired in short-axis and 4-chamber view. Reference images with identical scan parameters were acquired using the total-imaging-matrix (Tim) coil system with a total of 12 coil elements. Images were assessed by 2 observers in a consensus reading with regard to image quality, noise and presence of artifacts. Furthermore, signal-to-noise values were determined in phantom measurements. In phantom measurements signal-to-noise values were increased by 115-155% for the various cine sequences using the 32-element coil. Scoring of image quality yielded statistically significant increased image quality with the SSFP-GRAPPAx4, SSFP-TSENSEx4, and SSFP-TSENSEx6 sequence using the 32-element coil (P < 0.05). Similarly, scoring of image noise yielded a statistically significant lower noise rating with the SSFP-GRAPPAx4, GRE-GRAPPAx3, SSFP-TSENSEx4, and SSFP-TSENSEx6 sequence using the 32-element coil (P < 0.05). This study shows that cardiac cine imaging at 3 T using a 32-element body-array coil is feasible in healthy volunteers. Using a large number of coil elements with a favorable sensitivity profile supports faster image acquisition, with high diagnostic image quality even for high parallel imaging factors.

Readout and characterisation of new silicon pixel photodiode array for use in PET

International Nuclear Information System (INIS)

Hooper, P.; Ward, G.; Lerch, R.; Rozenfeld, A.

2002-01-01

Full text: Positron emission tomography (PET) is a functional imaging tool, which is able to quantify physiological, and biochemical processes in vivo using short-lived cyclotron-produced radiotracers. The main physical principle of PET is the simultaneous measurement of two 511 keV photons which are emitted in opposite directions following the annihilation of a positron in tissue. The accuracy of tracking these photons determines the accuracy of localising the radiotracer in the body, which is referred to as the spatial resolution of the system. Compared with conventional single photon imaging with gamma cameras, PET provides superior spatial resolution and sensitivity. However, compared with anatomical imaging techniques, the spatial resolution remains relatively poor at approximately 4-6 mm full width at half maximum (FWHM), compared with 1 mm FWHM for MRI. The Centre for Medical Radiation Physics at the University of Wollongong is developing a new Positron Emission Tomography (PET) detection sub-module that will significantly improve the spatial resolution of PET. The new sub-module design is simple and robust to minimise module assembly complications and is completely independent of photomultiplier tubes. The new sub-module has also been designed to maximise its flexibility for easy sub-module coupling so as to form a complete, customised, detection module to be used in PET scanners dedicated to human brain and breast, and small animal studies. A new computer controlled gantry allows the system to be used for PET and SPECT applications. Silicon 8x8 detector arrays have been developed by CMRP and will be optically coupled scintillation crystals and readout using the VIKING tM hybrid preamplifier chip to form the basis of the new module Characterisation of the pixel photodiode array has been performed to check the uniformity of the response of the array. This characterisation has been done using a pulsed, near infra-red laser diode system and alpha particles

Analysis of single-photon time resolution of FBK silicon photomultipliers

International Nuclear Information System (INIS)

Acerbi, Fabio; Ferri, Alessandro; Gola, Alberto; Zorzi, Nicola; Piemonte, Claudio

2015-01-01

We characterized and analyzed an important feature of silicon photomultipliers: the single-photon time resolution (SPTR). We characterized the SPTR of new RGB (Red–Green–Blue) type Silicon Photomultipliers and SPADs produced at FBK (Trento, Italy), studying its main limiting factors. We compared time resolution of 1×1 mm 2 and 3×3 mm 2 SiPMs and a single SiPM cell (i.e. a SPAD with integrated passive-quenching), employing a mode-locked pulsed laser with 2-ps wide pulses. We estimated the contribution of front-end electronic-noise, of cell-to-cell uniformity, and intrinsic cell time-resolution. At a single-cell level, we compared the results obtained with different layouts. With a circular cell with a top metallization covering part of the edge and enhancing the signal extraction, we reached ~20 ps FWHM of time resolution

A Full Parallel Event Driven Readout Technique for Area Array SPAD FLIM Image Sensors

Directory of Open Access Journals (Sweden)

Kaiming Nie

2016-01-01

Full Text Available This paper presents a full parallel event driven readout method which is implemented in an area array single-photon avalanche diode (SPAD image sensor for high-speed fluorescence lifetime imaging microscopy (FLIM. The sensor only records and reads out effective time and position information by adopting full parallel event driven readout method, aiming at reducing the amount of data. The image sensor includes four 8 × 8 pixel arrays. In each array, four time-to-digital converters (TDCs are used to quantize the time of photons’ arrival, and two address record modules are used to record the column and row information. In this work, Monte Carlo simulations were performed in Matlab in terms of the pile-up effect induced by the readout method. The sensor’s resolution is 16 × 16. The time resolution of TDCs is 97.6 ps and the quantization range is 100 ns. The readout frame rate is 10 Mfps, and the maximum imaging frame rate is 100 fps. The chip’s output bandwidth is 720 MHz with an average power of 15 mW. The lifetime resolvability range is 5–20 ns, and the average error of estimated fluorescence lifetimes is below 1% by employing CMM to estimate lifetimes.

Test of multi-anode photomultiplier tubes for the LHCb scintillator pad detector

CERN Document Server

Aguiló, Ernest; Comerma-Montells, A; Garrido, Lluis; Gascon, David; Graciani, Ricardo; Grauges, Eugeni; Vilasis Cardona, Xavier; Xirgu, Xavier; Bohner, Gerard; Bonnefoy, Romeo; Borras, David; Cornat, Remi; Crouau, Michel; Deschamps, Olivier; Jacquet, Philippe; Lecoq, Jacques; Monteil, Stephane; Perret, Pascal; Reinmuth, Guy

2005-01-01

The LHCb experiment (The LHCb Technical Proposal, CERN/LHCC 98-4) is designed to study B meson physics in the LHC proton-proton collider at CERN. The Scintillator Pad Detector (SPD) has been designed to complete the calorimeter information performing an e/gamma identification for the experiment level-0 trigger system. The detection technology consists in transmitting scintillation light by means of both Wavelength Shifting and clear fibers to fast multi- anode photomultiplier tubes. In this paper, it is described the instrumentation and setup used to characterize the baseline photomultiplier solution (Hamamatsu R5900-00-M64) together with the scintillators and optical fibers for the SPD at LHCb.

Desarrollo de un circuito integrado de múltiples canales para Silicon fotomultiplicador arrays lectura

CERN Document Server

Comerma i Montells, Albert

2013-10-31

The aim of this thesis is to present a solution for the readout of Silicon Photo-Multipliers (SiPMs) arrays improving currently implemented systems. Using as a starting point previous designs with similar objectives a novel current mode input stage has been designed and tested. To start with the design a valid model has been used to generate realistic output from the SiPMs depending on light input. Design has been performed in first place focusing in general applications for medical imaging Positron Emission Tomography (PET) and then using the same topology for a more constrained design in particle detectors (upgrade of Tracker detector at LHCb experiment). A 16 channel ASIC for PET applications including the novel input stage has demonstrated an excellent timing measurement with good energy resolution measurement and pile-up detection. This document starts with the analysis of the requirements needed to fit such a system. Followed by a detailed description of the input stage and analog processing. Signal is ...

Preparatory Study of Photomultiplier Tubes of 10-inch and 3-inch Diameter for KM3NeT Underwater Neutrino Telescope

International Nuclear Information System (INIS)

Aiello, S.; Giordano, V.; Leonora, E.

2015-01-01

Large area photomultipliers are widely used in neutrino and astro-particle detectors to measure Cherenkov light in media like water or ice. The key element of these detectors are the so-called 'optical module', which consists of a photodetector enclosed in a transparent pressure-resistant container to protect it and ensure good light transmission. KM3NeT collaboration aims to construct an underwater 'hybrid' neutrino telescope by using two models detection unit. The 'tower' detection unit will be composed of large area 10-inch photomultipliers tube enclosed into 13-inch glass vessel sphere. In the 'string' detection unit instead, the light detector will be the 'digital optical module' (DOM) a glass vessel of 17-inch with 31 photomultipliers of 3- inch diameter looking upwards and downwards. The choice of two different kinds of photomultipliers, obliges us to investigate their main characteristics. Noise pulses at the anode of each photomultiplier strongly affect the performance of the detector. A large study was conducted on noise pulses of large area photomultipliers, considering time and charge distributions of dark pulses, pre-pulses, delayed pulses, and after-pulses. The contribution to noise pulses due to the presence of the external glass vessels was also studied. Moreover the presence of the Earth's magnetic field should modify quantities like gain and transit time spread in photomultipliers and we will deeply investigate on this. (authors)

Prostate cancer: body-array versus endorectal coil MR imaging at 3 T--comparison of image quality, localization, and staging performance.

NARCIS (Netherlands)

Heijmink, S.W.T.P.J.; Futterer, J.J.; Hambrock, T.; Takahashi, S.; Scheenen, T.W.J.; Huisman, H.J.; Hulsbergen-van de Kaa, C.A.; Knipscheer, B.C.; Kiemeney, L.A.L.M.; Witjes, J.A.; Barentsz, J.O.

2007-01-01

PURPOSE: To prospectively compare image quality and accuracy of prostate cancer localization and staging with body-array coil (BAC) versus endorectal coil (ERC) T2-weighted magnetic resonance (MR) imaging at 3 T, with histopathologic findings as the reference standard. MATERIALS AND METHODS: After

Bi-dimensional arrays of SPAD for time-resolved single photon imaging

International Nuclear Information System (INIS)

Tudisco, S.; Lanzano, L.; Musumeci, F.; Neri, L.; Privitera, S.; Scordino, A.; Condorelli, G.; Fallica, G.; Mazzillo, M.; Sanfilippo, D.; Valvo, G.

2009-01-01

Many scientific areas like astronomy, biophysics, biomedicine, nuclear and plasma science, etc. are interested in the development of a new time-resolved single photon imaging device. Such a device represents today one of the most challenging goals in the field of photonics. In collaboration with Catania R and D staff of ST-Microelectronics (STM) we created, during the last few years, a new avalanche photosensor-Single Photon Avalanche Diode (SPAD) able to detect and count, with excellent performance, single photons. Further we will discuss the possible realization of a single photon imaging device through the many elements integration (bi-dimensional arrays) of SPADs. In order to achieve the goal, it is also important to develop an appropriate readout strategy able to address the time information of each individual sensor and in order to read a great number of elements easily. First prototypes were designed and manufactured by STM and the results are reported here. In the paper we will discuss in particular: (i) sensor performance (gain, photodetection efficiency, timing, after-pulsing, etc.); (ii) array performance (layout, cross-talk, etc.); (iii) readout strategy (quenching, electronics), and (iv) first imaging results (general performance).

Self characterization of a coded aperture array for neutron source imaging

Energy Technology Data Exchange (ETDEWEB)

Volegov, P. L., E-mail: volegov@lanl.gov; Danly, C. R.; Guler, N.; Merrill, F. E.; Wilde, C. H. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States); Fittinghoff, D. N. [Livermore National Laboratory, Livermore, California 94550 (United States)

2014-12-15

The neutron imaging system at the National Ignition Facility (NIF) is an important diagnostic tool for measuring the two-dimensional size and shape of the neutrons produced in the burning deuterium-tritium plasma during the stagnation stage of inertial confinement fusion implosions. Since the neutron source is small (∼100 μm) and neutrons are deeply penetrating (>3 cm) in all materials, the apertures used to achieve the desired 10-μm resolution are 20-cm long, triangular tapers machined in gold foils. These gold foils are stacked to form an array of 20 apertures for pinhole imaging and three apertures for penumbral imaging. These apertures must be precisely aligned to accurately place the field of view of each aperture at the design location, or the location of the field of view for each aperture must be measured. In this paper we present a new technique that has been developed for the measurement and characterization of the precise location of each aperture in the array. We present the detailed algorithms used for this characterization and the results of reconstructed sources from inertial confinement fusion implosion experiments at NIF.

Development and characterisation of a front-end ASIC for macro array of photo-detectors of large dimensions

International Nuclear Information System (INIS)

Conforti Di Lorenzo, S.

2010-10-01

The coverage of large areas of photo-detection is a crucial element of experiments studying high energy atmospheric cosmic showers and neutrinos from different sources. The objective of this project is to realize big detectors using thousands of photomultipliers (PMT). The project proposes to segment the large surface of photo-detection into macro pixels consisting of an array of 16 PMT of 12 inches (2*2 m 2 ), connected to an autonomous front-end electronics which works in without-trigger data acquisition mode placed near the array. This is possible thanks to the microelectronics progress that allows to integrate the readout and the signal processing, of all the multipliers, in the same circuit (ASIC) named PARISROC (Photomultiplier Array Integrated ins SiGe Read Out Chip). The ASIC must only send out the digital data by network to the surface central data storage. The PARISROC chip made in AM's Silicon Germanium (SiGe) 0.35 μm technology, integrates 16 independent channels for each PMT of the array, providing charge and time measurements. The first prototype of PARISROC chip has a total surface of 19 mm 2 . The ASIC measurements have led to the realization of a second prototype. Important measurements were performed in terms of noise, dynamic range, readout frequency (from 10 MHz to 40 MHz), time measurements (TDC improvements) and charge measurements (Slow shaper improvements). This new prototype of PARISROC-2 has been tested and the characterisation has shown a good overall behavior and the verification of the improvements. (author)

Advanced 3-D Ultrasound Imaging: 3-D Synthetic Aperture Imaging using Fully Addressed and Row-Column Addressed 2-D Transducer Arrays

DEFF Research Database (Denmark)

Bouzari, Hamed

the important diagnostic information in a noninvasive manner. Diagnostic and therapeutic decisions often require accurate estimates of e.g., organ, cyst, or tumor volumes. 3-D ultrasound imaging can provide these measurements without relying on the geometrical assumptions and operator-dependent skills involved...... is one of the factors for the widespread use of ultrasound imaging. The high price tag on the high quality 3-D scanners is limiting their market share. Row-column addressing of 2-D transducer arrays is a low cost alternative to fully addressed 2-D arrays, for 3-D ultrasound imaging. Using row....... Based on a set of acoustical measurements the center frequency, bandwidth, surface pressure, sensitivity, and acoustical cross-talks were evaluated and discussed. The imaging quality assessments were carried out based on Field II simulations as well as phantom measurements. Moreover, an analysis...

Characterization of large-area photomultipliers under low magnetic fields: Design and performance of the magnetic shielding for the Double Chooz neutrino experiment

International Nuclear Information System (INIS)

Calvo, E.; Cerrada, M.; Fernandez-Bedoya, C.; Gil-Botella, I.; Palomares, C.; Rodriguez, I.; Toral, F.; Verdugo, A.

2010-01-01

A precise quantitative measurement of the effect of low magnetic fields in Hamamatsu R7081 photomultipliers has been performed. These large-area photomultipliers will be used in the Double Chooz neutrino experiment. A magnetic shielding has been developed for these photomultipliers. Its design and performance is also reported in this paper.

Stability and lifetime testing of photomultiplier detectors for the Earth observing system SOLSTICE program

Science.gov (United States)

Hadler, Joshua A.; van de Kop, Toni; Drake, Virginia A.; McClintock, William E.; Murphy, John; Rodgers, Paul

1998-10-01

The primary objective of the Earth Observing System (EOS) Solar Stellar Irradiance Comparison Experiment (SOLSTICE) is to accurately measure the absolute value of the solar UV irradiance at the top of the earth's atmosphere for a minimum mission lifetime of 5 years. To meet this objective, SOLSTICE employs a unique design to determine changes in instrument performance by routinely observing a series of early-type stars and comparing the irradiances directly with the solar value. Although the comparison techniques allows us to track instrument performance, the success of the SOLSTICE experiment depends upon photomultiplier detectors which have graceful degradation properties. Therefore, we have established a laboratory program to evaluate the characteristics of photomultiplier tubes which are exposed to long term fluxes similar to those we expected to encounter in flight. Three types of Hamamatsu photomultiplier tubes were tested as candidates for use in the EOS-SOLSTICE project. The results of these studies: pulse height distribution; quantum efficiency; surface maps,; and lifetime analysis are presented in this paper.

A flexible coil array for high resolution magnetic resonance imaging at 7 Tesla

International Nuclear Information System (INIS)

Kriegl, R.

2015-01-01

Magnetic resonance imaging (MRI), among other imaging techniques, has become a major backbone of modern medical diagnostics. MRI enables the non-invasive combined, identification of anatomical structures, functional and chemical properties, especially in soft tissues. Nonetheless, applications requiring very high spatial and/or temporal resolution are often limited by the available signal-to-noise ratio (SNR) in MR experiments. Since first clinical applications, image quality in MRI has been constantly improved by applying one or several of the following strategies: increasing the static magnetic field strength, improvement of the radiofrequency (RF) detection system, development of specialized acquisition sequences and optimization of image reconstruction techniques. This work is concerned with the development of highly sensitive RF detection systems for biomedical ultra-high field MRI. In particular, auto-resonant RF coils based on transmission line technology are investigated. These resonators may be fabricated on flexible substrate which enables form-fitting of the RF detector to the target anatomy, leading to a significant SNR gain. The main objective of this work is the development of a flexible RF coil array for high-resolution MRI on a human whole-body 7 T MR scanner. With coil arrays, the intrinsically high SNR of small surface coils may be exploited for an extended field of view. Further, parallel imaging techniques are accessible with RF array technology, allowing acceleration of the image acquisition. Secondly, in this PhD project a novel design for transmission line resonators is developed, that brings an additional degree of freedom in geometric design and enables the fabrication of large multi-turn resonators for high field MR applications. This thesis describes the development, successful implementation and evaluation of novel, mechanically flexible RF devices by analytical and 3D electromagnetic simulations, in bench measurements and in MRI

Broadband image sensor array based on graphene-CMOS integration

Science.gov (United States)

Goossens, Stijn; Navickaite, Gabriele; Monasterio, Carles; Gupta, Shuchi; Piqueras, Juan José; Pérez, Raúl; Burwell, Gregory; Nikitskiy, Ivan; Lasanta, Tania; Galán, Teresa; Puma, Eric; Centeno, Alba; Pesquera, Amaia; Zurutuza, Amaia; Konstantatos, Gerasimos; Koppens, Frank

2017-06-01

Integrated circuits based on complementary metal-oxide-semiconductors (CMOS) are at the heart of the technological revolution of the past 40 years, enabling compact and low-cost microelectronic circuits and imaging systems. However, the diversification of this platform into applications other than microcircuits and visible-light cameras has been impeded by the difficulty to combine semiconductors other than silicon with CMOS. Here, we report the monolithic integration of a CMOS integrated circuit with graphene, operating as a high-mobility phototransistor. We demonstrate a high-resolution, broadband image sensor and operate it as a digital camera that is sensitive to ultraviolet, visible and infrared light (300-2,000 nm). The demonstrated graphene-CMOS integration is pivotal for incorporating 2D materials into the next-generation microelectronics, sensor arrays, low-power integrated photonics and CMOS imaging systems covering visible, infrared and terahertz frequencies.

MR imaging of the prostate at 3 Tesla: comparison of an external phased-array coil to imaging with an endorectal coil at 1.5 Tesla.

Science.gov (United States)

Sosna, Jacob; Pedrosa, Ivan; Dewolf, William C; Mahallati, Houman; Lenkinski, Robert E; Rofsky, Neil M

2004-08-01

To qualitatively compare the image quality of torso phased-array 3-Tesla (3T) imaging of the prostate with that of endorectal 1.5-Tesla imaging. Twenty cases of torso phased-array prostate imaging performed at 3-Tesla with FSE T2 weighted images were evaluated by two readers independently for visualization of the posterior border (PB), seminal vesicles (SV), neurovascular bundles (NVB), and image quality rating (IQR). Studies were performed at large fields of view(FOV) (25 cm) (14 cases) (3TL) and smaller FOV (14 cm) (19 cases) (3TS). A comparison was made to 20 consecutive cases of 1.5-T endorectal evaluation performed during the same time period.Results. 3TL produced a significantly better image quality compared with the small FOV for PB (P = .0001), SV (P =.0001), and IQR (P = .0001). There was a marginally significant difference within the NVB category (P = .0535). 3TL produced an image of similar quality to image quality at 1.5 T for PB (P = .3893), SV (P = .8680), NB (P = .2684), and IQR (P = .8599). Prostate image quality at 3T with a torso phased-array coil can be comparable with that of endorectal 1.5-T imaging. These findings suggest that additional options are now available for magnetic resonance imaging of the prostate gland.

Dynamic range broadening for photomultipliers in kinetic spectrophotometry

International Nuclear Information System (INIS)

Rumas, V.K.

1983-01-01

The circuit of switching on a photomultiplier with prestage modulation developed for kinetic spectrophotometry purposes is described. Distinguishing features of the scheme are wide range of control pulse duration (40 nc - 2.5 mc) and direct transistor photostart by laser light pulse. In the case of PM prestage modulation for the second dynode modulation depth attains 400 while PM opening time constitutes 40 nc

A simple method to improve the spatial uniformity of venetian-blind photomultiplier tubes

International Nuclear Information System (INIS)

Santos, J.M.F. dos; Veloso, J.F.C.A.; Morgado, R.E.

1996-01-01

An improvement in the uniformity of venetian-blind photomultiplier tubes has been achieved by reducing the voltage difference between the first and second dynodes. The method has been applied to a gas proportional scintillation counter (GPSC) instrumented with a venetian-blind photomultiplier (PMT). When exposed to a 20-mm collimated 5.9-keV x-ray beam, an overall improvement in energy resolution for the GPSC/PMT combination from 20% to 11.5% was achieved. An alternative method that reduces the photocathode-to-first-dynode voltage was less effective and resulted in a severe degradation of detector energy resolution

Analysis of single-photon time resolution of FBK silicon photomultipliers

Energy Technology Data Exchange (ETDEWEB)

Acerbi, Fabio, E-mail: acerbi@fbk.eu; Ferri, Alessandro; Gola, Alberto; Zorzi, Nicola; Piemonte, Claudio

2015-07-01

We characterized and analyzed an important feature of silicon photomultipliers: the single-photon time resolution (SPTR). We characterized the SPTR of new RGB (Red–Green–Blue) type Silicon Photomultipliers and SPADs produced at FBK (Trento, Italy), studying its main limiting factors. We compared time resolution of 1×1 mm{sup 2} and 3×3 mm{sup 2} SiPMs and a single SiPM cell (i.e. a SPAD with integrated passive-quenching), employing a mode-locked pulsed laser with 2-ps wide pulses. We estimated the contribution of front-end electronic-noise, of cell-to-cell uniformity, and intrinsic cell time-resolution. At a single-cell level, we compared the results obtained with different layouts. With a circular cell with a top metallization covering part of the edge and enhancing the signal extraction, we reached ~20 ps FWHM of time resolution.

Three-dimensional imaging through turbid media based on polarization-difference liquid-crystal microlens array

Science.gov (United States)

Xin, Zhaowei; Wei, Dong; Li, Dapeng; Xie, Xingwang; Chen, Mingce; Zhang, Xinyu; Wang, Haiwei; Xie, Changsheng

2018-02-01

In this paper, a polarization difference liquid-crystal microlens array (PD-LCMLA) for three dimensional imaging application through turbid media is fabricated and demonstrated. This device is composed of a twisted nematic liquidcrystal cell (TNLCC), a polarizer and a liquid-crystal microlens array. The polarizer is sandwiched between the TNLCC and LCMLA to help the polarization difference system achieving the orthogonal polarization raw images. The prototyped camera for polarization difference imaging has been constructed by integrating the PD-LCMLA with an image sensor. The orthogonally polarized light-field images are recorded by switching the working state of the TNLCC. Here, by using a special microstructure in conjunction with the polarization-difference algorithm, we demonstrate that the three-dimensional information in the scattering media can be retrieved from the polarization-difference imaging system with an electrically tunable PD-LCMLA. We further investigate the system's potential function based on the flexible microstructure. The microstructure provides a wide operation range in the manipulation of incident beams and also emerges multiple operation modes for imaging applications, such as conventional planar imaging, polarization imaging mode, and polarization-difference imaging mode. Since the PD-LCMLA demonstrates a very low power consumption, multiple imaging modes and simple manufacturing, this kind of device presents a potential to be used in many other optical and electro-optical systems.

Phased Array Imaging of Complex-Geometry Composite Components.

Science.gov (United States)

Brath, Alex J; Simonetti, Francesco

2017-10-01

Progress in computational fluid dynamics and the availability of new composite materials are driving major advances in the design of aerospace engine components which now have highly complex geometries optimized to maximize system performance. However, shape complexity poses significant challenges to traditional nondestructive evaluation methods whose sensitivity and selectivity rapidly decrease as surface curvature increases. In addition, new aerospace materials typically exhibit an intricate microstructure that further complicates the inspection. In this context, an attractive solution is offered by combining ultrasonic phased array (PA) technology with immersion testing. Here, the water column formed between the complex surface of the component and the flat face of a linear or matrix array probe ensures ideal acoustic coupling between the array and the component as the probe is continuously scanned to form a volumetric rendering of the part. While the immersion configuration is desirable for practical testing, the interpretation of the measured ultrasonic signals for image formation is complicated by reflection and refraction effects that occur at the water-component interface. To account for refraction, the geometry of the interface must first be reconstructed from the reflected signals and subsequently used to compute suitable delay laws to focus inside the component. These calculations are based on ray theory and can be computationally intensive. Moreover, strong reflections from the interface can lead to a thick dead zone beneath the surface of the component which limits sensitivity to shallow subsurface defects. This paper presents a general approach that combines advanced computing for rapid ray tracing in anisotropic media with a 256-channel parallel array architecture. The full-volume inspection of complex-shape components is enabled through the combination of both reflected and transmitted signals through the part using a pair of arrays held in a yoke

Microfabricated optically pumped magnetometer arrays for biomedical imaging

Science.gov (United States)

Perry, A. R.; Sheng, D.; Krzyzewski, S. P.; Geller, S.; Knappe, S.

2017-02-01

Optically-pumped magnetometers have demonstrated magnetic field measurements as precise as the best superconducting quantum interference device magnetometers. Our group develops miniature alkali atom-based magnetic sensors using microfabrication technology. Our sensors do not require cryogenic cooling, and can be positioned very close to the sample, making these sensors an attractive option for development in the medical community. We will present our latest chip-scale optically-pumped gradiometer developed for array applications to image magnetic fields from the brain noninvasively. These developments should lead to improved spatial resolution, and potentially sensitive measurements in unshielded environments.

A novel, SiPM-array-based, monolithic scintillator detector for PET

International Nuclear Information System (INIS)

Schaart, Dennis R; Dam, Herman T van; Seifert, Stefan; Beekman, Freek J; Vinke, Ruud; Dendooven, Peter; Loehner, Herbert

2009-01-01

Silicon photomultipliers (SiPMs) are of great interest to positron emission tomography (PET), as they enable new detector geometries, for e.g., depth-of-interaction (DOI) determination, are MR compatible, and offer faster response and higher gain than other solid-state photosensors such as avalanche photodiodes. Here we present a novel detector design with DOI correction, in which a position-sensitive SiPM array is used to read out a monolithic scintillator. Initial characterization of a prototype detector consisting of a 4 x 4 SiPM array coupled to either the front or back surface of a 13.2 mm x 13.2 mm x 10 mm LYSO:Ce 3+ crystal shows that front-side readout results in significantly better performance than conventional back-side readout. Spatial resolutions 2 detector, equals 960 ps FWHM.

Multi-time-over-threshold technique for photomultiplier signal processing: Description and characterization of the SCOTT ASIC

International Nuclear Information System (INIS)

Ferry, S.; Guilloux, F.; Anvar, S.; Chateau, F.; Delagnes, E.; Gautard, V.; Louis, F.; Monmarthe, E.; Le Provost, H.; Russo, S.; Schuller, J.-P.; Stolarczyk, Th.; Vallage, B.; Zonca, E.

2012-01-01

KM3NeT aims to build a cubic-kilometer scale neutrino telescope in the Mediterranean Sea based on a 3D array of photomultiplier tubes. A dedicated ASIC, named SCOTT, has been developed for the readout electronics of the PMTs: it uses up to 16 adjustable thresholds to digitize the signals with the multi-time-over-threshold technique. Digital outputs of discriminators feed a circular sampling memory and a “first in first out” digital memory for derandomization. At the end of the data processing, the ASIC produces a digital waveform sampled at 800 MHz. A specific study was carried out to process PMT data and has showed that five specifically chosen thresholds are suited to reach the required timing precision. A dedicated method based on the duration of the signal over a given threshold allows an equivalent timing precision at any charge. A charge estimator using the information from the thresholds allows a charge determination within less than 20% up to 60 pe.

Multi-time-over-threshold technique for photomultiplier signal processing: Description and characterization of the SCOTT ASIC

Science.gov (United States)

Ferry, S.; Guilloux, F.; Anvar, S.; Chateau, F.; Delagnes, E.; Gautard, V.; Louis, F.; Monmarthe, E.; Le Provost, H.; Russo, S.; Schuller, J.-P.; Stolarczyk, Th.; Vallage, B.; Zonca, E.; Representing the KM3NeT Consortium

2012-12-01

KM3NeT aims to build a cubic-kilometer scale neutrino telescope in the Mediterranean Sea based on a 3D array of photomultiplier tubes. A dedicated ASIC, named SCOTT, has been developed for the readout electronics of the PMTs: it uses up to 16 adjustable thresholds to digitize the signals with the multi-time-over-threshold technique. Digital outputs of discriminators feed a circular sampling memory and a “first in first out” digital memory for derandomization. At the end of the data processing, the ASIC produces a digital waveform sampled at 800 MHz. A specific study was carried out to process PMT data and has showed that five specifically chosen thresholds are suited to reach the required timing precision. A dedicated method based on the duration of the signal over a given threshold allows an equivalent timing precision at any charge. A charge estimator using the information from the thresholds allows a charge determination within less than 20% up to 60 pe.

Accelerated proton echo planar spectroscopic imaging (PEPSI) using GRAPPA with a 32-channel phased-array coil.

Science.gov (United States)

Tsai, Shang-Yueh; Otazo, Ricardo; Posse, Stefan; Lin, Yi-Ru; Chung, Hsiao-Wen; Wald, Lawrence L; Wiggins, Graham C; Lin, Fa-Hsuan

2008-05-01

Parallel imaging has been demonstrated to reduce the encoding time of MR spectroscopic imaging (MRSI). Here we investigate up to 5-fold acceleration of 2D proton echo planar spectroscopic imaging (PEPSI) at 3T using generalized autocalibrating partial parallel acquisition (GRAPPA) with a 32-channel coil array, 1.5 cm(3) voxel size, TR/TE of 15/2000 ms, and 2.1 Hz spectral resolution. Compared to an 8-channel array, the smaller RF coil elements in this 32-channel array provided a 3.1-fold and 2.8-fold increase in signal-to-noise ratio (SNR) in the peripheral region and the central region, respectively, and more spatial modulated information. Comparison of sensitivity-encoding (SENSE) and GRAPPA reconstruction using an 8-channel array showed that both methods yielded similar quantitative metabolite measures (P > 0.1). Concentration values of N-acetyl-aspartate (NAA), total creatine (tCr), choline (Cho), myo-inositol (mI), and the sum of glutamate and glutamine (Glx) for both methods were consistent with previous studies. Using the 32-channel array coil the mean Cramer-Rao lower bounds (CRLB) were less than 8% for NAA, tCr, and Cho and less than 15% for mI and Glx at 2-fold acceleration. At 4-fold acceleration the mean CRLB for NAA, tCr, and Cho was less than 11%. In conclusion, the use of a 32-channel coil array and GRAPPA reconstruction can significantly reduce the measurement time for mapping brain metabolites. (c) 2008 Wiley-Liss, Inc.

Seismic Imaging of the Source Physics Experiment Site with the Large-N Seismic Array

Science.gov (United States)

Chen, T.; Snelson, C. M.; Mellors, R. J.

2017-12-01

The Source Physics Experiment (SPE) consists of a series of chemical explosions at the Nevada National Security Site. The goal of SPE is to understand seismic wave generation and propagation from these explosions. To achieve this goal, we need an accurate geophysical model of the SPE site. A Large-N seismic array that was deployed at the SPE site during one of the chemical explosions (SPE-5) helps us construct high-resolution local geophysical model. The Large-N seismic array consists of 996 geophones, and covers an area of approximately 2 × 2.5 km. The array is located in the northern end of the Yucca Flat basin, at a transition from Climax Stock (granite) to Yucca Flat (alluvium). In addition to the SPE-5 explosion, the Large-N array also recorded 53 weight drops. Using the Large-N seismic array recordings, we perform body wave and surface wave velocity analysis, and obtain 3D seismic imaging of the SPE site for the top crust of approximately 1 km. The imaging results show clear variation of geophysical parameter with local geological structures, including heterogeneous weathering layer and various rock types. The results of this work are being incorporated in the larger 3D modeling effort of the SPE program to validate the predictive models developed for the site.

Array of lead-glass blocks from OPAL

CERN Multimedia

OPAL was one of the 4 experiments at CERN's Large Electron Positron collider (LEP) which ran from 1989 - 2000. This array of 96 lead glass bricks formed part of the OPAL electromagnetic calorimeter. In total, there were 9440 lead glass counters in the OPAL electromagnetic calorimeter, made of Schott type SF57 glass and each block weighs about 25 kg and consists of 76% PbO by weight. Each block has a Hamamatsu R2238 photomultiplier glued on to it. The complete detector was in the form of a cylinder 7m long and 6m in diameter. It was used to measure the energy of electrons and photons produced in LEP electron positron collisions.

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

Directory of Open Access Journals (Sweden)

Jong-Ryul Yang

2016-03-01

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

Development and characterization of a TES optical imaging array for astrophysics applications

International Nuclear Information System (INIS)

Burney, J.; Bay, T.J.; Brink, P.L.; Cabrera, B.; Castle, J.P.; Romani, R.W.; Tomada, A.; Nam, S.W.; Miller, A.J.; Martinis, J.; Wang, E.; Kenny, T.; Young, B.A.

2004-01-01

Our research group has successfully developed photon detectors capable of both time-stamping and energy-resolving individual photons at very high rates in a wide band from the near-IR through optical and into the near-UV. We have fabricated 32-pixel arrays of these Transition-Edge Sensor (TES) devices and have mounted them in an adiabatic demagnetization refrigerator equipped with windows for direct imaging. We have characterized single pixel behavior; we have also begun operating multiple pixels simultaneously, starting the scaling process towards use of the full array. We emphasize the development of a metalized mask for our array that blocks photons from hitting the inter-pixel areas and reflects them onto the TESs. We also present calibration data on detector resolution, electronics noise, and optical alignment

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

Science.gov (United States)

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

2009-01-01

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

Frontend Receiver Electronics for High Frequency Monolithic CMUT-on-CMOS Imaging Arrays

Science.gov (United States)

Gurun, Gokce; Hasler, Paul; Degertekin, F. Levent

2012-01-01

This paper describes the design of CMOS receiver electronics for monolithic integration with capacitive micromachined ultrasonic transducer (CMUT) arrays for high-frequency intravascular ultrasound imaging. A custom 8-inch wafer is fabricated in a 0.35 μm two-poly, four-metal CMOS process and then CMUT arrays are built on top of the application specific integrated circuits (ASICs) on the wafer. We discuss advantages of the single-chip CMUT-on-CMOS approach in terms of receive sensitivity and SNR. Low-noise and high-gain design of a transimpedance amplifier (TIA) optimized for a forward-looking volumetric-imaging CMUT array element is discussed as a challenging design example. Amplifier gain, bandwidth, dynamic range and power consumption trade-offs are discussed in detail. With minimized parasitics provided by the CMUT-on-CMOS approach, the optimized TIA design achieves a 90 fA/√Hz input referred current noise, which is less than the thermal-mechanical noise of the CMUT element. We show successful system operation with a pulse-echo measurement. Transducer noise-dominated detection in immersion is also demonstrated through output noise spectrum measurement of the integrated system at different CMUT bias voltages. A noise figure of 1.8 dB is obtained in the designed CMUT bandwidth of 10 MHz to 20 MHz. PMID:21859585

7 Tesla 22-channel wrap-around coil array for cervical spinal cord and brainstem imaging.

Science.gov (United States)

Zhang, Bei; Seifert, Alan C; Kim, Joo-Won; Borrello, Joseph; Xu, Junqian

2017-10-01

Increased signal-to-noise ratio and blood oxygenation level-dependent sensitivity at 7 Tesla (T) have the potential to enable high-resolution imaging of the human cervical spinal cord and brainstem. We propose a new two-panel radiofrequency coil design for these regions to fully exploit the advantages of ultra-high field. A two-panel array, containing four transmit/receive and 18 receive-only elements fully encircling the head and neck, was constructed following simulations demonstrating the B1+ and specific absorption rate (SAR) benefits of two-panel over one-panel arrays. This array was compared with a previously reported posterior-only array and tested for safety using a phantom. Its anatomical, functional, and diffusion MRI performance was demonstrated in vivo. The two-panel array produced more uniform B1+ across the brainstem and cervical spinal cord without compromising SAR, and achieved 70% greater receive sensitivity than the posterior-only array. The two-panel design enabled acceleration of R = 2 × 2 in two dimensions or R = 3 in a single dimension. High quality in vivo anatomical, functional, and diffusion images of the human cervical spinal cord and brainstem were acquired. We have designed and constructed a wrap-around coil array with excellent performance for cervical spinal cord and brainstem MRI at 7T, which enables simultaneous human cervical spinal cord and brainstem functional MRI. Magn Reson Med 78:1623-1634, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Enhanced imaging of magnetic structures in micropatterned arrays of Co dots and antidots

Energy Technology Data Exchange (ETDEWEB)

Chiolerio, Alessandro [Physics Department Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Celasco, Edvige [Physics Department Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Materials and Microsystems Laboratory (chi lab)-LATEMAR Unit, Lungo Piazza d' Armi 6, Chivasso (Torino) (Italy); Celegato, Federica [INRIM, Strada delle Cacce 91, 10138 Torino (Italy); Guastella, Salvatore; Martino, Paola [Physics Department Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Allia, Paolo [Physics Department Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)], E-mail: paolo.allia@polito.it; Tiberto, Paola [INRIM, Strada delle Cacce 91, 10138 Torino (Italy); Pirri, Fabrizio [Physics Department Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Materials and Microsystems Laboratory (chi lab)-LATEMAR Unit, Lungo Piazza d' Armi 6, Chivasso (Torino) (Italy)

2008-10-15

A specific technique of numerical treatment of atomic force microscopy (AFM) and magnetic force microscopy (MFM) signal has been developed to enhance the quality of raw images, in order both to improve their contrast and to gain better insight on the sample topography and on the local arrangement of the magnetisation vector. Basically, the technique consists in computing the optimum conformal transformation that allows one to superimpose two AFM images of the same area, acquired performing subsequent scans whose fast scan axis were mutually perpendicular, and applying the inverse transform to the second image. After MFM image superposition, the two datasets were either summed or subtracted, in order to improve the magnetic contrast. Computations have been done in a Matlab workspace with the help of Image Processing Toolbox 4.2. Improved MFM images obtained on both dots and antidots thin evaporated Co arrays in the demagnetised state (after performing alternate field demagnetisation parallel and perpendicular to the array plane) have been interpreted. Samples consisting of large-size patterns (1x1 mm) of circular dots/antidots with square/hexagonal lattices and minimum diameters of 1 {mu}m were prepared by optical lithography. The magnetic film thickness was chosen depending on resist thickness, and varied between 25 and 150 nm, with a fixed ratio 1:4 between metal/resist film thickness. MFM was exploited to obtain images of either intra-dot or inter-antidot magnetic structures.

Comparison of blind imaging performance of Fizeau and Michelson type arrays for a partially resolved object

NARCIS (Netherlands)

Van der Avoort, C.; Den Herder, J.W.; Braat, J.

2005-01-01

This paper compares two well-known types of interferometer arrays for optical aperture synthesis. An analytical model for both types describes the expected output, in terms of photon counts. The goal is to characterize the performance of both types of array for blind imaging of a wide-field or

Characterization of orthogonal transfer array CCDs for the WIYN one degree imager

Science.gov (United States)

Lesser, Michael; Ouellette, David; Boroson, Todd; Harbeck, Daniel; Martin, Pierre; Jacoby, George; Cavin, John; Sawyer, David; Boggs, Kasey; Bredthauer, Richard

2012-03-01

The WIYN One Degree Imager (ODI) will provide a one degree field of view for the WIYN 3.5 m telescope located on Kitt Peak near Tucson, Arizona. Its focal plane consists of an 8x8 grid of Orthogonal Transfer Array (OTA) CCD detectors. These detectors are the STA2200 OTA CCDs designed and fabricated by Semiconductor Technology Associates, Inc. and backside processed at the University of Arizona Imaging Technology Laboratory. Several lot runs of the STA2200 detectors have been fabricated. We have backside processed devices from these different lots and provide detector performance characterization, including noise, CTE, cosmetics, quantum efficiency, and some orthogonal transfer characteristics. We discuss the performance differences for the devices with different silicon thickness and resistivity. A fully buttable custom detector package has been developed for this project which allows hybridization of the silicon detectors directly onto an aluminum nitride substrate with an embedded pin grid array. This package is mounted on a silicon-aluminum alloy which provides a flat imaging surface of less than 20 microns peakvalley at the -100 C operating temperature. Characterization of the package performance, including low temperature profilometry, is described in this paper.

Progress in GEM-based gaseous photomultipliers

CERN Document Server

Chechik, R; Breskin, Amos; Buzulutskov, A F; Guedes, G P; Mörmann, D; Singh, B K

2003-01-01

We discuss recent progress in gaseous photomultipliers (GPMTs) comprising UV-to-visible spectral range photocathodes (PCs) coupled to multiple Gas Electron Multipliers (GEM). The PCs may be either semitransparent or reflective ones directly deposited on the first-GEM surface. These detectors provide high gain, even in noble gases, are sensitive to single photons, have nanosecond time resolution, and offer good localization. The operation of CsI-based GPMTs in CF sub 4 opens new applications in Cherenkov detectors, where both the radiator and the photosensor operate in the same gas. The latest results on sealed visible-light detectors, combining bialkali PCs and Kapton-made GEMs are presented.

An efficient high-voltage power supply for a photomultiplier tube

NARCIS (Netherlands)

Ainutdinov, VM; Vonsovskii, NN; Kompaniets, KG; Kozyr, AI; Mikhailov, YV

2003-01-01

An adjustable power supply for a photomultiplier tube operating in the pulsed spectrometric mode with a wide range of linearity is described. The power consumed by the source is 50 mW. The output voltage is varied from 800 to 2000 V. The maximum ripple amplitude is 2.5 mV.

A silicon photomultiplier readout for time of flight neutron spectroscopy with {gamma}-ray detectors

Energy Technology Data Exchange (ETDEWEB)

Pietropaolo, A.; Gorini, G. [Dipartimento di Fisica ' ' G. Occhialini' ' and CNISM, Universita Degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano (Italy); Festa, G.; Andreani, C.; De Pascale, M. P.; Reali, E. [Dipartimento di Fisica and Centro NAST, Universita degli Studi di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133, Roma (Italy); Grazzi, F. [Istituto dei Sistemi Complessi-Consiglio Nazionale delle Ricerche, Via Madonna del Piano n.10, I-50019 Sesto Fiorentino, Firenze (Italy); Schooneveld, E. M. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX (United Kingdom)

2009-09-15

The silicon photomultiplier (SiPM) is a recently developed photosensor used in particle physics, e.g., for detection of minimum ionizing particles and/or Cherenkov radiation. Its performance is comparable to that of photomultiplier tubes, but with advantages in terms of reduced volume and magnetic field insensitivity. In the present study, the performance of a gamma ray detector made of an yttrium aluminum perovskite scintillation crystal and a SiPM-based readout is assessed for use in time of flight neutron spectroscopy. Measurements performed at the ISIS pulsed neutron source demonstrate the feasibility of {gamma}-detection based on the new device.

Development of a multi-channel horn mixer array for microwave imaging plasma diagnostics

International Nuclear Information System (INIS)

Ito, Naoki; Kuwahara, Daisuke; Nagayama, Yoshio

2015-01-01

Microwave to millimeter-wave diagnostics techniques, such as interferometry, reflectometry, scattering, and radiometry, have been powerful tools for diagnosing magnetically confined plasmas. The resultant measurements have clarified several physics issues, including instability, wave phenomena, and fluctuation-induced transport. Electron cyclotron emission imaging has been an important tool in the investigation of temperature fluctuations, while reflectometry has been employed to measure plasma density profiles and their fluctuations. We have developed a horn-antenna mixer array (HMA), a 50 - 110 GHz 1D antenna array, which can be easily stacked as a 2D array. This article describes an upgrade to the horn mixer array that combines well-characterized mixers, waveguide-to-microstrip line transitions, intermediate frequency amplifiers, and internal local oscillator modules using a monolithic microwave integrated circuit technology to improve system performance. We also report on the use of a multi-channel HMA system. (author)

Extension of photomultiplier tube dynamic range for the LHAASO-KM2A electromagnetic particle detectors

Energy Technology Data Exchange (ETDEWEB)

Lv, Hongkui, E-mail: lvhk@ihep.ac.cn [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Sheng, Xiangdong; He, Huihai; Liu, Jia [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Zhongquan [Shandong University, Jinan 250100 (China); Hou, Chao; Zhao, Jing [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

2015-05-01

In the Large High Altitude Air Shower Observatory (LHAASO), the 1 km{sup 2} array (KM2A) requires linear measurement of optical intensity with a wide dynamic range. Over 5000 photomultiplier tubes (PMTs) are employed in this experiment and developed as “two outputs” device (anode and dynode) to meet the relevant requirements. In this study, the linearity of the anode and the eighth dynode (DY8), which is limited by space charge effects and mainly related to the relative dynode voltage ratios of the PMT divider, is examined. A voltage divider for the Hamamatsu R11102 PMT is designed and a dramatically enhanced linearity is demonstrated. Test results show that this design can cover a wide dynamic range from 20 to 2×10{sup 5} photoelectrons and achieve a peak anode current of 380 mA at a PMT gain of 10{sup 5}, which satisfies the requirements of KM2A electromagnetic particle detectors. The circuit design has been successfully simulated using the simulation software Multisim. The details of PMT performance tests and simulations are described.

Extension of photomultiplier tube dynamic range for the LHAASO-KM2A electromagnetic particle detectors

Science.gov (United States)

Lv, Hongkui; Sheng, Xiangdong; He, Huihai; Liu, Jia; Zhang, Zhongquan; Hou, Chao; Zhao, Jing

2015-05-01

In the Large High Altitude Air Shower Observatory (LHAASO), the 1 km2 array (KM2A) requires linear measurement of optical intensity with a wide dynamic range. Over 5000 photomultiplier tubes (PMTs) are employed in this experiment and developed as "two outputs" device (anode and dynode) to meet the relevant requirements. In this study, the linearity of the anode and the eighth dynode (DY8), which is limited by space charge effects and mainly related to the relative dynode voltage ratios of the PMT divider, is examined. A voltage divider for the Hamamatsu R11102 PMT is designed and a dramatically enhanced linearity is demonstrated. Test results show that this design can cover a wide dynamic range from 20 to 2×105 photoelectrons and achieve a peak anode current of 380 mA at a PMT gain of 105, which satisfies the requirements of KM2A electromagnetic particle detectors. The circuit design has been successfully simulated using the simulation software Multisim. The details of PMT performance tests and simulations are described.

Extension of photomultiplier tube dynamic range for the LHAASO-KM2A electromagnetic particle detectors

International Nuclear Information System (INIS)

Lv, Hongkui; Sheng, Xiangdong; He, Huihai; Liu, Jia; Zhang, Zhongquan; Hou, Chao; Zhao, Jing

2015-01-01

In the Large High Altitude Air Shower Observatory (LHAASO), the 1 km 2 array (KM2A) requires linear measurement of optical intensity with a wide dynamic range. Over 5000 photomultiplier tubes (PMTs) are employed in this experiment and developed as “two outputs” device (anode and dynode) to meet the relevant requirements. In this study, the linearity of the anode and the eighth dynode (DY8), which is limited by space charge effects and mainly related to the relative dynode voltage ratios of the PMT divider, is examined. A voltage divider for the Hamamatsu R11102 PMT is designed and a dramatically enhanced linearity is demonstrated. Test results show that this design can cover a wide dynamic range from 20 to 2×10 5 photoelectrons and achieve a peak anode current of 380 mA at a PMT gain of 10 5 , which satisfies the requirements of KM2A electromagnetic particle detectors. The circuit design has been successfully simulated using the simulation software Multisim. The details of PMT performance tests and simulations are described

Fast tracking detector with fiber scintillators and a position sensitive photomultiplier

International Nuclear Information System (INIS)

Salomon, M.; Li, V.; Smith, G.; Wu, Y.S.

1988-11-01

We have studied the properties of a tracking detector composed of 32 fiber scintillators coupled to a multianode photomultiplier placed in a pion beam at TRIUMF. We measured the efficiency of the detector, as well as its tracking capabilities and double hit resolution

Development of a SiPM Camera for a Schwarzschild-Couder Cherenkov Telescope for the Cherenkov Telescope Array

CERN Document Server

Otte, A N; Dickinson, H.; Funk, S.; Jogler, T.; Johnson, C.A.; Karn, P.; Meagher, K.; Naoya, H.; Nguyen, T.; Okumura, A.; Santander, M.; Sapozhnikov, L.; Stier, A.; Tajima, H.; Tibaldo, L.; Vandenbroucke, J.; Wakely, S.; Weinstein, A.; Williams, D.A.

2015-01-01

We present the development of a novel 11328 pixel silicon photomultiplier (SiPM) camera for use with a ground-based Cherenkov telescope with Schwarzschild-Couder optics as a possible medium-sized telescope for the Cherenkov Telescope Array (CTA). The finely pixelated camera samples air-shower images with more than twice the optical resolution of cameras that are used in current Cherenkov telescopes. Advantages of the higher resolution will be a better event reconstruction yielding improved background suppression and angular resolution of the reconstructed gamma-ray events, which is crucial in morphology studies of, for example, Galactic particle accelerators and the search for gamma-ray halos around extragalactic sources. Packing such a large number of pixels into an area of only half a square meter and having a fast readout directly attached to the back of the sensors is a challenging task. For the prototype camera development, SiPMs from Hamamatsu with through silicon via (TSV) technology are used. We give ...

Photon-Counting Arrays for Time-Resolved Imaging

Directory of Open Access Journals (Sweden)

I. Michel Antolovic

2016-06-01

Full Text Available The paper presents a camera comprising 512 × 128 pixels capable of single-photon detection and gating with a maximum frame rate of 156 kfps. The photon capture is performed through a gated single-photon avalanche diode that generates a digital pulse upon photon detection and through a digital one-bit counter. Gray levels are obtained through multiple counting and accumulation, while time-resolved imaging is achieved through a 4-ns gating window controlled with subnanosecond accuracy by a field-programmable gate array. The sensor, which is equipped with microlenses to enhance its effective fill factor, was electro-optically characterized in terms of sensitivity and uniformity. Several examples of capture of fast events are shown to demonstrate the suitability of the approach.

Counting efficiency formulae for two, three or four photomultiplier systems

International Nuclear Information System (INIS)

Grau Malonda, A.

1993-01-01

Counting efficiency formulae as a function of the non-detection probability and the electron distributions for systems with two, three or dour photomultipliers are obtained in this paper. It is assumed that the photocathode electron emission follows the Poisson distribution. The obtained formulae are basic to compute the counting efficiency in liquid scintillation spectrometers

Optimization of the digital Silicon Photomultiplier for Cherenkov light detection

International Nuclear Information System (INIS)

Frach, T

2012-01-01

The Silicon Photomultiplier is a promising alternative to fast vacuum photodetectors. We developed a fully digital implementation of the Silicon Photomultiplier. The sensor is based on a single photon avalanche photodiode (SPAD) integrated in a standard CMOS process. Photons are detected directly by sensing the voltage at the SPAD anode using a dedicated cell electronics block next to each diode. This block also contains active quenching and recharge circuits as well as a one bit memory for the selective inhibit of detector cells. A balanced trigger network is used to propagate the trigger signal from all cells to the integrated time-to-digital converter. Photons are detected and counted as digital signals, thus making the sensor less susceptible to temperature variations and electronic noise. The integration with CMOS logic has the added benefit of low power consumption and possible integration of data post-processing in the sensor. In this paper, we discuss the sensor architecture together with its characteristics, and its possible optimizations for applications requiring the detection of Cherenkov light.

Distributed Read-out Imaging Device array for astronomical observations in UV/VIS

NARCIS (Netherlands)

Hijmering, R.A.

2009-01-01

STJ (Superconducting Tunneling Junctions) are being developed as spectro-photometers in wavelengths ranging from the NIR to X-rays. 10x12 arrays of STJs have already been successfully used as optical imaging spectrometers with the S-Cam 3, on the William Hershel Telescope on La Palma and on the

Evaluation of ultrasonic array imaging algorithms for inspection of a coarse grained material

Science.gov (United States)

Van Pamel, A.; Lowe, M. J. S.; Brett, C. R.

2014-02-01

Improving the ultrasound inspection capability for coarse grain metals remains of longstanding interest to industry and the NDE research community and is expected to become increasingly important for next generation power plants. A test sample of coarse grained Inconel 625 which is representative of future power plant components has been manufactured to test the detectability of different inspection techniques. Conventional ultrasonic A, B, and C-scans showed the sample to be extraordinarily difficult to inspect due to its scattering behaviour. However, in recent years, array probes and Full Matrix Capture (FMC) imaging algorithms, which extract the maximum amount of information possible, have unlocked exciting possibilities for improvements. This article proposes a robust methodology to evaluate the detection performance of imaging algorithms, applying this to three FMC imaging algorithms; Total Focusing Method (TFM), Phase Coherent Imaging (PCI), and Decomposition of the Time Reversal Operator with Multiple Scattering (DORT MSF). The methodology considers the statistics of detection, presenting the detection performance as Probability of Detection (POD) and probability of False Alarm (PFA). The data is captured in pulse-echo mode using 64 element array probes at centre frequencies of 1MHz and 5MHz. All three algorithms are shown to perform very similarly when comparing their flaw detection capabilities on this particular case.

Preliminary studies of microchannel plate photomultiplier tube neutron detectors for flight test applications

International Nuclear Information System (INIS)

Dolan, K.W.

1978-10-01

Electrical, mechanical, thermal, and neutron response data indicate that microchannel plate photomultiplier tubes are viable candidates as miniature, ruggedized neutron detectors for flight test applications in future weapon systems

Development of an application specific scintimammography detector based on a crystal scintillator array and a PSPMT

CERN Document Server

Majewski, S; Goode, A; Kross, B J; Steinbach, D; Weisenberger, A; Williams, M; Wojci, R

1998-01-01

We report the results of studies conducted with small field of view scintimammography camera based on a position-sensitive photomultiplier tube (5'' Hamamatsu R3292) and several pixelized crystal scintillator arrays made of YAP, CsI(Na) and NaI(Tl) scintillators. Laboratory tests and pre-clinical phantom studies were conducted to compare and optimize the performances of the prototypes with special emphasis on spatial resolution (approx 2-3mm) and sufficient energy resolution for scatter rejection.

Evaluation of electrical crosstalk in high-density photodiode arrays for X-ray imaging applications

International Nuclear Information System (INIS)

Ji Fan; Juntunen, Mikko; Hietanen, Iiro

2009-01-01

Electrical crosstalk is one of the important parameters in the photodiode array detector for X-ray imaging applications, and it becomes more important when the density of the photodiode array becomes higher. This paper presents the design of the high-density photodiode array with 250 μm pitch and 50 μm gap. The electrical crosstalk of the demonstrated samples is evaluated and compared with different electrode configurations: cathode bias mode and anode bias mode. The measurement results show good electrical crosstalk, ∼0.23%, in cathode bias mode regardless of the bias voltage, and slightly decreased or increased electrical crosstalk in anode bias mode. Moreover, the quantum efficiency is also evaluated from the same samples, and it behaves similar to the electrical crosstalk. Finally, some design guidance of the high-density photodiode array is given based on the discussion.

Camera calibration strategy of the SST-1M prototype of the Cherenokov Telescope Array

CERN Document Server

Prandini, E; Lyard, E.; Schioppa, E. jr.; Neronov, A.; Bilnik, W.; Błocki, J.; Bogacz, L.; Bulik, T.; Cadoux, F.; Christov, A.; Curyło, M.; della Volpe, D.; Dyrda, M.; Favre, Y.; Frankowski, A.; Grudnik, Ł.; Grudzińska, M.; Idźkowski, B.; Jamrozy, M.; Janiak, M.; Kasperek, J.; Lalik, K.; Mach, E.; Mandat, D.; Marszałek, A.; Michałowski, J.; Moderski, R.; Montaruli, T.; Niemiec, J.; Ostrowski, M.; Paśko, P.; Pech, M.; Porcelli, A.; Rameez, M.; Rajda, P.; Schovanek, P.; Seweryn, K.; Skowron, K.; Sliusar, V.; Sowiński, M.; Stawarz, Ł.; Stodulska, M.; Stodulski, M.; Toscano, S.; Pujadas, I. Troyano; Walter, R.; Więcek, M.; Zagdański, A.; Ziętara, K.; Żychowski, P.

2015-01-01

The SST-1M telescope is one of the prototypes under construction proposed to be part of the future Cherenkov Telescope Array. It uses a standard Davis-Cotton design for the optics and telescope structure, with a dish diameter of 4 meters and a large field-of-view of 9 degrees. The innovative camera design is composed of a photo-detection plane with 1296 pixels including entrance window, light concentrators, Silicon Photomultipliers (SiPMs), and pre-amplifier stages together with a fully digital readout and trigger electronics, DigiCam. In this contribution we give a general description of the analysis chain designed for the SST-1M prototype. In particular we focus on the calibration strategy used to convert the SiPM signals registered by DigiCam to the quantities needed for Cherenkov image analysis. The calibration is based on an online feedback system to stabilize the gain of the SiPMs, as well as dedicated events (dark count, pedestal, and light flasher events) to be taken during the normal operation of the...

Imaging 2015 Mw 7.8 Gorkha Earthquake and Its Aftershock Sequence Combining Multiple Calibrated Global Seismic Arrays

Science.gov (United States)

LI, B.; Ghosh, A.

2016-12-01

The 2015 Mw 7.8 Gorkha earthquake provides a good opportunity to study the tectonics and earthquake hazards in the Himalayas, one of the most seismically active plate boundaries. Details of the seismicity patterns and associated structures in the Himalayas are poorly understood mainly due to limited instrumentation. Here, we apply a back-projection method to study the mainshock rupture and the following aftershock sequence using four large aperture global seismic arrays. All the arrays show eastward rupture propagation of about 130 km and reveal similar evolution of seismic energy radiation, with strong high-frequency energy burst about 50 km north of Kathmandu. Each single array, however, is typically limited by large azimuthal gap, low resolution, and artifacts due to unmodeled velocity structures. Therefore, we use a self-consistent empirical calibration method to combine four different arrays to image the Gorkha event. It greatly improves the resolution, can better track rupture and reveal details that cannot be resolved by any individual array. In addition, we also use the same arrays at teleseismic distances and apply a back-projection technique to detect and locate the aftershocks immediately following the Gorkha earthquake. We detect about 2.5 times the aftershocks recorded by the Advance National Seismic System comprehensive earthquake catalog during the 19 days following the mainshock. The aftershocks detected by the arrays show an east-west trend in general, with majority of the aftershocks located at the eastern part of the rupture patch and surrounding the rupture zone of the largest Mw 7.3 aftershock. Overall spatiotemporal aftershock pattern agrees well with global catalog, with our catalog showing more details relative to the standard global catalog. The improved aftershock catalog enables us to better study the aftershock dynamics, stress evolution in this region. Moreover, rapid and better imaging of aftershock distribution may aid rapid response

MO-G-17A-01: Innovative High-Performance PET Imaging System for Preclinical Imaging and Translational Researches

Energy Technology Data Exchange (ETDEWEB)

Sun, X [University of Texas MD Anderson Cancer Center, Houston, TX (United States); Lou, K [University of Texas MD Anderson Cancer Center, Houston, TX (United States); Rice University, Houston, TX (United States); Deng, Z [Tsinghua University, Beijing (China); Shao, Y

2014-06-15

Purpose: To develop a practical and compact preclinical PET with innovative technologies for substantially improved imaging performance required for the advanced imaging applications. Methods: Several key components of detector, readout electronics and data acquisition have been developed and evaluated for achieving leapfrogged imaging performance over a prototype animal PET we had developed. The new detector module consists of an 8×8 array of 1.5×1.5×30 mm{sup 3} LYSO scintillators with each end coupled to a latest 4×4 array of 3×3 mm{sup 2} Silicon Photomultipliers (with ∼0.2 mm insensitive gap between pixels) through a 2.0 mm thick transparent light spreader. Scintillator surface and reflector/coupling were designed and fabricated to reserve air-gap to achieve higher depth-of-interaction (DOI) resolution and other detector performance. Front-end readout electronics with upgraded 16-ch ASIC was newly developed and tested, so as the compact and high density FPGA based data acquisition and transfer system targeting 10M/s coincidence counting rate with low power consumption. The new detector module performance of energy, timing and DOI resolutions with the data acquisition system were evaluated. Initial Na-22 point source image was acquired with 2 rotating detectors to assess the system imaging capability. Results: No insensitive gaps at the detector edge and thus it is capable for tiling to a large-scale detector panel. All 64 crystals inside the detector were clearly separated from a flood-source image. Measured energy, timing, and DOI resolutions are around 17%, 2.7 ns and 1.96 mm (mean value). Point source image is acquired successfully without detector/electronics calibration and data correction. Conclusion: Newly developed advanced detector and readout electronics will be enable achieving targeted scalable and compact PET system in stationary configuration with >15% sensitivity, ∼1.3 mm uniform imaging resolution, and fast acquisition counting rate

MO-G-17A-01: Innovative High-Performance PET Imaging System for Preclinical Imaging and Translational Researches

International Nuclear Information System (INIS)

Sun, X; Lou, K; Deng, Z; Shao, Y

2014-01-01

Purpose: To develop a practical and compact preclinical PET with innovative technologies for substantially improved imaging performance required for the advanced imaging applications. Methods: Several key components of detector, readout electronics and data acquisition have been developed and evaluated for achieving leapfrogged imaging performance over a prototype animal PET we had developed. The new detector module consists of an 8×8 array of 1.5×1.5×30 mm 3 LYSO scintillators with each end coupled to a latest 4×4 array of 3×3 mm 2 Silicon Photomultipliers (with ∼0.2 mm insensitive gap between pixels) through a 2.0 mm thick transparent light spreader. Scintillator surface and reflector/coupling were designed and fabricated to reserve air-gap to achieve higher depth-of-interaction (DOI) resolution and other detector performance. Front-end readout electronics with upgraded 16-ch ASIC was newly developed and tested, so as the compact and high density FPGA based data acquisition and transfer system targeting 10M/s coincidence counting rate with low power consumption. The new detector module performance of energy, timing and DOI resolutions with the data acquisition system were evaluated. Initial Na-22 point source image was acquired with 2 rotating detectors to assess the system imaging capability. Results: No insensitive gaps at the detector edge and thus it is capable for tiling to a large-scale detector panel. All 64 crystals inside the detector were clearly separated from a flood-source image. Measured energy, timing, and DOI resolutions are around 17%, 2.7 ns and 1.96 mm (mean value). Point source image is acquired successfully without detector/electronics calibration and data correction. Conclusion: Newly developed advanced detector and readout electronics will be enable achieving targeted scalable and compact PET system in stationary configuration with >15% sensitivity, ∼1.3 mm uniform imaging resolution, and fast acquisition counting rate capability

Front-end receiver electronics for high-frequency monolithic CMUT-on-CMOS imaging arrays.

Science.gov (United States)

Gurun, Gokce; Hasler, Paul; Degertekin, F

2011-08-01

This paper describes the design of CMOS receiver electronics for monolithic integration with capacitive micromachined ultrasonic transducer (CMUT) arrays for highfrequency intravascular ultrasound imaging. A custom 8-inch (20-cm) wafer is fabricated in a 0.35-μm two-poly, four-metal CMOS process and then CMUT arrays are built on top of the application specific integrated circuits (ASICs) on the wafer. We discuss advantages of the single-chip CMUT-on-CMOS approach in terms of receive sensitivity and SNR. Low-noise and high-gain design of a transimpedance amplifier (TIA) optimized for a forward-looking volumetric-imaging CMUT array element is discussed as a challenging design example. Amplifier gain, bandwidth, dynamic range, and power consumption trade-offs are discussed in detail. With minimized parasitics provided by the CMUT-on-CMOS approach, the optimized TIA design achieves a 90 fA/√Hz input-referred current noise, which is less than the thermal-mechanical noise of the CMUT element. We show successful system operation with a pulseecho measurement. Transducer-noise-dominated detection in immersion is also demonstrated through output noise spectrum measurement of the integrated system at different CMUT bias voltages. A noise figure of 1.8 dB is obtained in the designed CMUT bandwidth of 10 to 20 MHz.

Reduction of space charge effects and tests of larger samples of photomultipliers for the EDDA experiment

Science.gov (United States)

Ackerstaff, K.; Bisplinghoff, J.; Bollmann, R.; Cloth, P.; Dohrmann, F.; Diehl, O.; Dorner, G.; Drüke, V.; Engelhardt, H. J.; Eisenhardt, S.; Ernst, J.; Eversheim, P. D.; Filges, D.; Fritz, S.; Gasthuber, M.; Gebel, R.; Gross, A.; Gross-Hardt, R.; Hinterberger, F.; Jahn, R.; Lahr, U.; Langkau, R.; Lippert, G.; Mayer-Kuckuk, T.; Maschuw, R.; Mertler, G.; Metsch, B.; Mosel, F.; Paetz gen. Schieck, H.; Petry, H. R.; Prasuhn, D.; v. Przewoski, B.; Radtke, M.; Rohdjess, H.; Rosendaal, D.; von Rossen, P.; Scheid, H.; Schirm, N.; Schwandt, F.; Scobel, W.; Theis, D.; Weber, J.; Wiedmann, W.; Woller, K.; Ziegler, R.; EDDA Collaboration

1993-10-01

For the EDDA experiment at COSY, the response of the small, linear focused photomultipliers Hamamatsu R 1450 and R 1355 has been studied with fast light pulses generating yields up to 2 × 10 3 photoelectrons/cm 2 or peak currents of 24 mA. Linearity was obtained with a tapered bleeder chain at a tolerable loss of gain. The serial test of altogether 140 photomultipliers revealed the close correlation between single electron and amplitude resolution. The influence of the photoelectron statistics on this correlation is discussed.

Fiber array based hyperspectral Raman imaging for chemical selective analysis of malaria-infected red blood cells

Energy Technology Data Exchange (ETDEWEB)

Brückner, Michael [Leibniz Institute of Photonic Technology, 07745 Jena (Germany); Becker, Katja [Justus Liebig University Giessen, Biochemistry and Molecular Biology, 35392 Giessen (Germany); Popp, Jürgen [Leibniz Institute of Photonic Technology, 07745 Jena (Germany); Friedrich Schiller University Jena, Institute for Physical Chemistry, 07745 Jena (Germany); Friedrich Schiller University Jena, Abbe Centre of Photonics, 07745 Jena (Germany); Frosch, Torsten, E-mail: torsten.frosch@uni-jena.de [Leibniz Institute of Photonic Technology, 07745 Jena (Germany); Friedrich Schiller University Jena, Institute for Physical Chemistry, 07745 Jena (Germany); Friedrich Schiller University Jena, Abbe Centre of Photonics, 07745 Jena (Germany)

2015-09-24

A new setup for Raman spectroscopic wide-field imaging is presented. It combines the advantages of a fiber array based spectral translator with a tailor-made laser illumination system for high-quality Raman chemical imaging of sensitive biological samples. The Gaussian-like intensity distribution of the illuminating laser beam is shaped by a square-core optical multimode fiber to a top-hat profile with very homogeneous intensity distribution to fulfill the conditions of Koehler. The 30 m long optical fiber and an additional vibrator efficiently destroy the polarization and coherence of the illuminating light. This homogeneous, incoherent illumination is an essential prerequisite for stable quantitative imaging of complex biological samples. The fiber array translates the two-dimensional lateral information of the Raman stray light into separated spectral channels with very high contrast. The Raman image can be correlated with a corresponding white light microscopic image of the sample. The new setup enables simultaneous quantification of all Raman spectra across the whole spatial area with very good spectral resolution and thus outperforms other Raman imaging approaches based on scanning and tunable filters. The unique capabilities of the setup for fast, gentle, sensitive, and selective chemical imaging of biological samples were applied for automated hemozoin analysis. A special algorithm was developed to generate Raman images based on the hemozoin distribution in red blood cells without any influence from other Raman scattering. The new imaging setup in combination with the robust algorithm provides a novel, elegant way for chemical selective analysis of the malaria pigment hemozoin in early ring stages of Plasmodium falciparum infected erythrocytes. - Highlights: • Raman hyperspectral imaging allows for chemical selective analysis of biological samples with spatial heterogeneity. • A homogeneous, incoherent illumination is essential for reliable

Fiber array based hyperspectral Raman imaging for chemical selective analysis of malaria-infected red blood cells

International Nuclear Information System (INIS)

Brückner, Michael; Becker, Katja; Popp, Jürgen; Frosch, Torsten

2015-01-01

A new setup for Raman spectroscopic wide-field imaging is presented. It combines the advantages of a fiber array based spectral translator with a tailor-made laser illumination system for high-quality Raman chemical imaging of sensitive biological samples. The Gaussian-like intensity distribution of the illuminating laser beam is shaped by a square-core optical multimode fiber to a top-hat profile with very homogeneous intensity distribution to fulfill the conditions of Koehler. The 30 m long optical fiber and an additional vibrator efficiently destroy the polarization and coherence of the illuminating light. This homogeneous, incoherent illumination is an essential prerequisite for stable quantitative imaging of complex biological samples. The fiber array translates the two-dimensional lateral information of the Raman stray light into separated spectral channels with very high contrast. The Raman image can be correlated with a corresponding white light microscopic image of the sample. The new setup enables simultaneous quantification of all Raman spectra across the whole spatial area with very good spectral resolution and thus outperforms other Raman imaging approaches based on scanning and tunable filters. The unique capabilities of the setup for fast, gentle, sensitive, and selective chemical imaging of biological samples were applied for automated hemozoin analysis. A special algorithm was developed to generate Raman images based on the hemozoin distribution in red blood cells without any influence from other Raman scattering. The new imaging setup in combination with the robust algorithm provides a novel, elegant way for chemical selective analysis of the malaria pigment hemozoin in early ring stages of Plasmodium falciparum infected erythrocytes. - Highlights: • Raman hyperspectral imaging allows for chemical selective analysis of biological samples with spatial heterogeneity. • A homogeneous, incoherent illumination is essential for reliable

Highly accelerated acquisition and homogeneous image reconstruction with rotating RF coil array at 7T-A phantom based study.

Science.gov (United States)

Li, Mingyan; Zuo, Zhentao; Jin, Jin; Xue, Rong; Trakic, Adnan; Weber, Ewald; Liu, Feng; Crozier, Stuart

2014-03-01

Parallel imaging (PI) is widely used for imaging acceleration by means of coil spatial sensitivities associated with phased array coils (PACs). By employing a time-division multiplexing technique, a single-channel rotating radiofrequency coil (RRFC) provides an alternative method to reduce scan time. Strategically combining these two concepts could provide enhanced acceleration and efficiency. In this work, the imaging acceleration ability and homogeneous image reconstruction strategy of 4-element rotating radiofrequency coil array (RRFCA) was numerically investigated and experimental validated at 7T with a homogeneous phantom. Each coil of RRFCA was capable of acquiring a large number of sensitivity profiles, leading to a better acceleration performance illustrated by the improved geometry-maps that have lower maximum values and more uniform distributions compared to 4- and 8-element stationary arrays. A reconstruction algorithm, rotating SENSitivity Encoding (rotating SENSE), was proposed to provide image reconstruction. Additionally, by optimally choosing the angular sampling positions and transmit profiles under the rotating scheme, phantom images could be faithfully reconstructed. The results indicate that, the proposed technique is able to provide homogeneous reconstructions with overall higher and more uniform signal-to-noise ratio (SNR) distributions at high reduction factors. It is hoped that, by employing the high imaging acceleration and homogeneous imaging reconstruction ability of RRFCA, the proposed method will facilitate human imaging for ultra high field MRI. Copyright © 2013 Elsevier Inc. All rights reserved.

InGaAs focal plane arrays for low-light-level SWIR imaging

Science.gov (United States)

MacDougal, Michael; Hood, Andrew; Geske, Jon; Wang, Jim; Patel, Falgun; Follman, David; Manzo, Juan; Getty, Jonathan

2011-06-01

Aerius Photonics will present their latest developments in large InGaAs focal plane arrays, which are used for low light level imaging in the short wavelength infrared (SWIR) regime. Aerius will present imaging in both 1280x1024 and 640x512 formats. Aerius will present characterization of the FPA including dark current measurements. Aerius will also show the results of development of SWIR FPAs for high temperaures, including imagery and dark current data. Finally, Aerius will show results of using the SWIR camera with Aerius' SWIR illuminators using VCSEL technology.

The Use of Radiation Detectors in Medicine: The Future of Molecular Imaging and Multimodality Imaging: Advantages and Technological Challenges (3/3)

CERN Multimedia

CERN. Geneva

2009-01-01

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

Characterization of a prototype matrix of Silicon PhotoMultipliers

Energy Technology Data Exchange (ETDEWEB)

Dinu, N. [Laboratory of Linear Accelerator (LAL), IN2P3-CNRS, 91898 Orsay (France)], E-mail: dinu@lal.in2p3.fr; Barrillon, P.; Bazin, C. [Laboratory of Linear Accelerator (LAL), IN2P3-CNRS, 91898 Orsay (France); Belcari, N.; Bisogni, M.G. [Universita di Pisa, Dipartimento di Fisica ' E. Fermi' , 56127 Pisa (Italy); INFN, Sezione di Pisa, 56127 Pisa (Italy); Bondil-Blin, S. [Laboratory of Linear Accelerator (LAL), IN2P3-CNRS, 91898 Orsay (France); Boscardin, M. [Fondazione Bruno Kessler (FBK-irst), 38050 Trento (Italy); Chaumat, V. [Laboratory of Linear Accelerator (LAL), IN2P3-CNRS, 91898 Orsay (France); Collazuol, G. [Scuola Normale Superiore (SNS), 56127 Pisa (Italy); INFN, Sezione di Pisa, 56127 Pisa (Italy); De La Taille, C. [Laboratory of Linear Accelerator (LAL), IN2P3-CNRS, 91898 Orsay (France); Del Guerra, A. [Universita di Pisa, Dipartimento di Fisica ' E. Fermi' , 56127 Pisa (Italy); INFN, Sezione di Pisa, 56127 Pisa (Italy); Llosa, G. [Universita di Pisa, Dipartimento di Fisica ' E. Fermi' , 56127 Pisa (Italy); Marcatili, S. [Universita di Pisa, Dipartimento di Fisica ' E. Fermi' , 56127 Pisa (Italy); INFN, Sezione di Pisa, 56127 Pisa (Italy); Melchiorri, M.; Piemonte, C. [Fondazione Bruno Kessler (FBK-irst), 38050 Trento (Italy); Puill, V. [Laboratory of Linear Accelerator (LAL), IN2P3-CNRS, 91898 Orsay (France); Tarolli, A. [Fondazione Bruno Kessler (FBK-irst), 38050 Trento (Italy); Vagnucci, J.F. [Laboratory of Linear Accelerator (LAL), IN2P3-CNRS, 91898 Orsay (France); Zorzi, N. [Fondazione Bruno Kessler (FBK-irst), 38050 Trento (Italy)

2009-10-21

This work reports on the electrical as well as the optical characterizations of a prototype matrix of Silicon PhotoMultipliers (SiPM). The electrical test consists of the measurement of the static (breakdown voltage, quenching resistance, post-breakdown dark current) as well as the dynamic characteristics (gain, dark count rate). The optical test consists of the estimation of the photon detection efficiency as a function of wavelength as well as operation voltage.

Characterization of a prototype matrix of Silicon PhotoMultipliers

International Nuclear Information System (INIS)

Dinu, N.; Barrillon, P.; Bazin, C.; Belcari, N.; Bisogni, M.G.; Bondil-Blin, S.; Boscardin, M.; Chaumat, V.; Collazuol, G.; De La Taille, C.; Del Guerra, A.; Llosa, G.; Marcatili, S.; Melchiorri, M.; Piemonte, C.; Puill, V.; Tarolli, A.; Vagnucci, J.F.; Zorzi, N.

2009-01-01

This work reports on the electrical as well as the optical characterizations of a prototype matrix of Silicon PhotoMultipliers (SiPM). The electrical test consists of the measurement of the static (breakdown voltage, quenching resistance, post-breakdown dark current) as well as the dynamic characteristics (gain, dark count rate). The optical test consists of the estimation of the photon detection efficiency as a function of wavelength as well as operation voltage.

Free-running ADC- and FPGA-based signal processing method for brain PET using GAPD arrays

Energy Technology Data Exchange (ETDEWEB)

Hu, Wei [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-Dong, Gangnam-Gu, Seoul 135-710 (Korea, Republic of); Choi, Yong, E-mail: ychoi.image@gmail.com [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Hong, Key Jo [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Kang, Jihoon [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-Dong, Gangnam-Gu, Seoul 135-710 (Korea, Republic of); Jung, Jin Ho [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Huh, Youn Suk [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-Dong, Gangnam-Gu, Seoul 135-710 (Korea, Republic of); Lim, Hyun Keong; Kim, Sang Su [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Kim, Byung-Tae [Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-Dong, Gangnam-Gu, Seoul 135-710 (Korea, Republic of); Chung, Yonghyun [Department of Radiological Science, Yonsei University College of Health Science, 234 Meaji, Heungup Wonju, Kangwon-Do 220-710 (Korea, Republic of)

2012-02-01

Currently, for most photomultiplier tube (PMT)-based PET systems, constant fraction discriminators (CFD) and time to digital converters (TDC) have been employed to detect gamma ray signal arrival time, whereas anger logic circuits and peak detection analog-to-digital converters (ADCs) have been implemented to acquire position and energy information of detected events. As compared to PMT the Geiger-mode avalanche photodiodes (GAPDs) have a variety of advantages, such as compactness, low bias voltage requirement and MRI compatibility. Furthermore, the individual read-out method using a GAPD array coupled 1:1 with an array scintillator can provide better image uniformity than can be achieved using PMT and anger logic circuits. Recently, a brain PET using 72 GAPD arrays (4 Multiplication-Sign 4 array, pixel size: 3 mm Multiplication-Sign 3 mm) coupled 1:1 with LYSO scintillators (4 Multiplication-Sign 4 array, pixel size: 3 mm Multiplication-Sign 3 mm Multiplication-Sign 20 mm) has been developed for simultaneous PET/MRI imaging in our laboratory. Eighteen 64:1 position decoder circuits (PDCs) were used to reduce GAPD channel number and three off-the-shelf free-running ADC and field programmable gate array (FPGA) combined data acquisition (DAQ) cards were used for data acquisition and processing. In this study, a free-running ADC- and FPGA-based signal processing method was developed for the detection of gamma ray signal arrival time, energy and position information all together for each GAPD channel. For the method developed herein, three DAQ cards continuously acquired 18 channels of pre-amplified analog gamma ray signals and 108-bit digital addresses from 18 PDCs. In the FPGA, the digitized gamma ray pulses and digital addresses were processed to generate data packages containing pulse arrival time, baseline value, energy value and GAPD channel ID. Finally, these data packages were saved to a 128 Mbyte on-board synchronous dynamic random access memory (SDRAM) and

Muon tracking system with Silicon Photomultipliers

International Nuclear Information System (INIS)

Arneodo, F.; Benabderrahmane, M.L.; Dahal, S.; Di Giovanni, A.; Pazos Clemens, L.; Candela, A.; D'Incecco, M.; Sablone, D.; Franchi, G.

2015-01-01

We report the characterisation and performance of a low cost muon tracking system consisting of plastic scintillator bars and Silicon Photomultipliers equipped with a customised front-end electronics based on a fast preamplifier network. This system can be used as a detector test bench for astroparticle physics and for educational and outreach purposes. We investigated the device behaviour in self-trigger and coincidence mode, without using LED and pulse generators, showing that with a relatively simple set up a complete characterisation work can be carried out. A high definition oscilloscope, which can easily be found in many university physics or engineering departments, has been used for triggering and data acquisition. Its capabilities have been exploited to discriminate real particles from the background

Muon tracking system with Silicon Photomultipliers

Energy Technology Data Exchange (ETDEWEB)

Arneodo, F.; Benabderrahmane, M.L.; Dahal, S. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Di Giovanni, A., E-mail: adriano.digiovanni@nyu.edu [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Pazos Clemens, L. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Candela, A.; D' Incecco, M.; Sablone, D. [Gran Sasso National Laboratory of INFN, Assergi (Italy); Franchi, G. [AGE Scientific Srl, Capezzano Pianore (Italy)

2015-11-01

We report the characterisation and performance of a low cost muon tracking system consisting of plastic scintillator bars and Silicon Photomultipliers equipped with a customised front-end electronics based on a fast preamplifier network. This system can be used as a detector test bench for astroparticle physics and for educational and outreach purposes. We investigated the device behaviour in self-trigger and coincidence mode, without using LED and pulse generators, showing that with a relatively simple set up a complete characterisation work can be carried out. A high definition oscilloscope, which can easily be found in many university physics or engineering departments, has been used for triggering and data acquisition. Its capabilities have been exploited to discriminate real particles from the background.

Performance of a thermal imager employing a hybrid pyroelectric detector array with MOSFET readout

International Nuclear Information System (INIS)

Watton, R.; Mansi, M.V.

1988-01-01

A thermal imager employing a two-dimensional hybrid array of pyroelectric detectors with MOSFET readout has been built. The design and theoretical performance of the detector are discussed, and the results of performance measurements are presented. 8 references

Development of Very Long Baseline Interferometry (VLBI) techniques in New Zealand: Array simulation, image synthesis and analysis

Science.gov (United States)

Weston, S. D.

2008-04-01

This thesis presents the design and development of a process to model Very Long Base Line Interferometry (VLBI) aperture synthesis antenna arrays. In line with the Auckland University of Technology (AUT) Institute for Radiophysics and Space Research (IRSR) aims to develop the knowledge, skills and experience within New Zealand, extensive use of existing radio astronomical software has been incorporated into the process namely AIPS (Astronomical Imaging Processing System), MIRIAD (a radio interferometry data reduction package) and DIFMAP (a program for synthesis imaging of visibility data from interferometer arrays of radio telescopes). This process has been used to model various antenna array configurations for two proposed New Zealand sites for antenna in a VLBI array configuration with existing Australian facilities and a passable antenna at Scott Base in Antarctica; and the results are presented in an attempt to demonstrate the improvement to be gained by joint trans-Tasman VLBI observation. It is hoped these results and process will assist the planning and placement of proposed New Zealand radio telescopes for cooperation with groups such as the Australian Long Baseline Array (LBA), others in the Pacific Rim and possibly globally; also potential future involvement of New Zealand with the SKA. The developed process has also been used to model a phased building schedule for the SKA in Australia and the addition of two antennas in New Zealand. This has been presented to the wider astronomical community via the Royal Astronomical Society of New Zealand Journal, and is summarized in this thesis with some additional material. A new measure of quality ("figure of merit") for comparing the original model image and final CLEAN images by utilizing normalized 2-D cross correlation is evaluated as an alternative to the existing subjective visual operator image comparison undertaken to date by other groups. This new unit of measure is then used ! in the presentation of the

Infrared detectors, focal plane arrays, and imaging sensors; Proceedings of the Meeting, Orlando, FL, Mar. 30, 31, 1989

Science.gov (United States)

Dereniak, Eustace L.; Sampson, Robert T.

1989-10-01

The present conference on advancements in IR detectors, Schottky-barrier focal plane arrays, CCD image analysis, and HgCdTe materials gives attention to a 256 x 256 PtSi array for IR astronomy, proposals for a second-generation meteosat's advanced optical payload, cryogenic bipolar technology for on-focal-plane signal processing, a parallel cellular processing system for fast generation of perspective plots, and ultrahigh-speed CCD image sensors for scanning applications. Also discussed are MBE GaAs rib waveguide experiments at 10.6 microns, an interferometric thermal detector, the development status of superconducting IR detector research, the absorption coefficients of n-type Hg(1-x)Cd(x)Te samples, and the influence of the surface channel on crosstalk in HgCdTe photovoltaic arrays.

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

International Nuclear Information System (INIS)

Stratos, David; Maria, Georgiou; Eleftherios, Fysikopoulos; George, Loudos

2013-01-01

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

Characterization of three high efficiency and blue sensitive silicon photomultipliers

Energy Technology Data Exchange (ETDEWEB)

Otte, Adam Nepomuk, E-mail: otte@gatech.edu; Garcia, Distefano; Nguyen, Thanh; Purushotham, Dhruv

2017-02-21

We report about the optical and electrical characterization of three high efficiency and blue sensitive Silicon photomultipliers from FBK, Hamamatsu, and SensL. Key features of the tested devices when operated at 90% breakdown probability are peak photon detection efficiencies between 40% and 55%, temperature dependencies of gain and PDE that are less than 1%/°C, dark rates of ∼50 kHz/mm{sup 2} at room temperature, afterpulsing of about 2%, and direct optical crosstalk between 6% and 20%. The characteristics of all three devices impressively demonstrate how the Silicon-photomultiplier technology has improved over the past ten years. It is further demonstrated how the voltage and temperature characteristics of a number of quantities can be parameterized on the basis of physical models. The models provide a deeper understanding of the device characteristics over a wide bias and temperature range. They also serve as examples how producers could provide the characteristics of their SiPMs to users. A standardized parameterization of SiPMs would enable users to find the optimal SiPM for their application and the operating point of SiPMs without having to perform measurements thus significantly reducing design and development cycles.

Iterative reconstruction of SiPM light response functions in a square-shaped compact gamma camera

Science.gov (United States)

Morozov, A.; Alves, F.; Marcos, J.; Martins, R.; Pereira, L.; Solovov, V.; Chepel, V.

2017-05-01

Compact gamma cameras with a square-shaped monolithic scintillator crystal and an array of silicon photomultipliers (SiPMs) are actively being developed for applications in areas such as small animal imaging, cancer diagnostics and radiotracer guided surgery. Statistical methods of position reconstruction, which are potentially superior to the traditional centroid method, require accurate knowledge of the spatial response of each photomultiplier. Using both Monte Carlo simulations and experimental data obtained with a camera prototype, we show that the spatial response of all photomultipliers (light response functions) can be parameterized with axially symmetric functions obtained iteratively from flood field irradiation data. The study was performed with a camera prototype equipped with a 30  ×  30  ×  2 mm3 LYSO crystal and an 8  ×  8 array of SiPMs for 140 keV gamma rays. The simulations demonstrate that the images, reconstructed with the maximum likelihood method using the response obtained with the iterative approach, exhibit only minor distortions: the average difference between the reconstructed and the true positions in X and Y directions does not exceed 0.2 mm in the central area of 22  ×  22 mm2 and 0.4 mm at the periphery of the camera. A similar level of image distortions is shown experimentally with the camera prototype.

Wide aperture scintillation hodoscope with FEU-143 photomultipliers

International Nuclear Information System (INIS)

Afanas'ev, L.G.; Ivanov, M.A.; Karpukhin, V.V.; Komarov, V.I.; Kulikov, A.V.; Yazkov, V.V.

1993-01-01

Scintillation hodoscopes with FEU-143 photomultipliers are described. Every of two hodoscopes consists of 8 elements each of length 1400 mm and cross section 56x56 mm. The time and amplitude characteristics were obtained in real conditions of the physical experiment at the Protvino U-70 accelerator. A resolution on time difference between hits of two hodoscopes is 224 ps. A separation of pions and protons by their ionization losses is also provided at momenta less than 1000 MeV/c. 5 refs.; 8 figs.; 1 tab

Performance of the hybrid photomultiplier tube (HPMT)

Energy Technology Data Exchange (ETDEWEB)

Schomaker, R.J. [B.V. Delft Electronische Producten, Roden (Netherlands)

1995-12-31

The HPMT, which may be an alternative for PhotoMultiplier Tubes (PMT`s) in many applications, is a vacuum tube in which the latest technologies of photocathodes and photodiodes are combined. Photo-electrons are accelerated and bombarding a reversely biased PIN diode, where they create many electron-hole-pairs. The resulting charge pulse can be amplified and further processed. The HPMT shows many superior characteristics compared to regular PMT`s, because it does not suffer the statistical fluctuations common for electron multiplication processes. An energy resolution of up to 14 photo-electrons will be presented, together with striking figures for dynamic range and timing behavior.

An innovative silicon photomultiplier digitizing camera for gamma-ray astronomy

Czech Academy of Sciences Publication Activity Database

Heller, M.; Schioppa, E.jr.; Porcelli, A.; Pujadas, I.T.; Zietara, K.; della Volpe, D.; Montaruli, T.; Cadoux, F.; Favre, Y.; Aguilar, J.A.; Christov, A.; Prandini, E.; Rajda, P.; Rameez, M.; Bilnik, W.; Blocki, J.; Bogacz, L.; Borkowski, J.; Bulik, T.; Frankowski, A.; Grudzinska, M.; Idzkowski, B.; Jamrozy, M.; Janiak, M.; Kasperek, J.; Lalik, K.; Lyard, E.; Mach, E.; Mandát, Dušan; Marszalek, A.; Medina Miranda, L. D.; Michałowski, J.; Moderski, R.; Neronov, A.; Niemiec, J.; Ostrowski, M.; Pasko, P.; Pech, Miroslav; Schovánek, Petr; Seweryn, K.; Sliusar, V.; Skowron, K.; Stawarz, L.; Stodulska, M.; Stodulski, M.; Walter, R.; Wiecek, M.; Zagdanski, A.

2017-01-01

Roč. 77, č. 1 (2017), s. 1-31, č. článku 47. ISSN 1434-6044 R&D Projects: GA MŠk LE13012; GA MŠk LG14019 Institutional support: RVO:68378271 Keywords : silicon photomultiplier * digitizing camera * gamma-ray astronomy Subject RIV: BF - Elementary Particles and High Energy Physics OBOR OECD: Particles and field physics Impact factor: 5.331, year: 2016

Measurement of the modulation transfer function of a charge-coupled device array by the combination of the self-imaging effect and slanted edge method.

Science.gov (United States)

Najafi, Sedigheh; Madanipour, Khosro

2013-07-01

In this paper, by a combination of the self-imaging effect for Ronchi gratings and the standard slanted edge modulation transfer function (MTF) measurement method for CCD cameras, the MTF of the CCD array without optics is measured. For this purpose, a Ronchi-type grating is illuminated by an expanded He-Ne laser. A self-image of the grating appears without optics on the CCD array that is located on the Talbot distance. The lines of the self-image of the grating are used as a slanted edge array. This method has all the advantages of the slanted edge method, and also since the array of the edge is ready, the total area of the CCD can be tested. The measured MTF is related to the CCD array without optics.

An amplifier for VUV photomultiplier operating in cryogenic environment

International Nuclear Information System (INIS)

Arneodo, F.; Benabderrahmane, M.L.; Dahal, S.; Di Giovanni, A.; D'Inzeo, M.; Franchi, G.; Pazos Clemens, L.

2016-01-01

We present the characterisation of an amplifier potentially interesting for noble liquid detectors. The design has been conceived considering the requirements of low power consumption (less than 30 mW), low noise, amplification factor of 10 at 100 MHz and use of commercial components. The amplifier has been integrated onto an electronic board with a voltage divider to operate an Hamamatsu R11410 photomultiplier tube (used in XENON1T, Aprile et al. (2014) [1] dark matter experiment).

An amplifier for VUV photomultiplier operating in cryogenic environment

Energy Technology Data Exchange (ETDEWEB)

Arneodo, F.; Benabderrahmane, M.L.; Dahal, S. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Di Giovanni, A., E-mail: adriano.digiovanni@nyu.edu [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); D' Inzeo, M.; Franchi, G. [Age Scientific srl – Capezzano Pianore (Italy); Pazos Clemens, L. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates)

2016-07-11

We present the characterisation of an amplifier potentially interesting for noble liquid detectors. The design has been conceived considering the requirements of low power consumption (less than 30 mW), low noise, amplification factor of 10 at 100 MHz and use of commercial components. The amplifier has been integrated onto an electronic board with a voltage divider to operate an Hamamatsu R11410 photomultiplier tube (used in XENON1T, Aprile et al. (2014) [1] dark matter experiment).

Sensitivity of an eight-element phased array coil in 3 Tesla MR imaging: a basic analysis.

Science.gov (United States)

Hiratsuka, Yoshiyasu; Miki, Hitoshi; Kikuchi, Keiichi; Kiriyama, Ikuko; Mochizuki, Teruhito; Takahashi, Shizue; Sadamoto, Kazuhiko

2007-01-01

To evaluate the performance advantages of an 8-element phased array head coil (8 ch coil) over a conventional quadrature-type birdcage head coil (QD coil) with regard to the signal-to-noise ratio (SNR) and image uniformity in 3 Tesla magnetic resonance (MR) imaging. We scanned a phantom filled with silicon oil using an 8 ch coil and a QD coil in a 3T MR imaging system and compared the SNR and image uniformity obtained from T(1)-weighted spin echo (SE) images and T(2)-weighted fast SE images between the 2 coils. We also visually evaluated images from 4 healthy volunteers. The SNR with the 8 ch coil was approximately twice that with the QD coil in the region of interest (ROI), which was set as 75% of the area in the center of the phantom images. With regard to the spatial variation of sensitivity, the SNR with the 8 ch coil was lower at the center of the images than at the periphery, whereas the SNR with the QD coil exhibited an inverse pattern. At the center of the images with the 8 ch coil, the SNR was somewhat lower, and that distribution was relatively flat compared to that in the periphery. Image uniformity varied less with the 8 ch coil than with the QD coil on both imaging sequences. The 8 ch phased array coil was useful for obtaining high quality 3T images because of its higher SNR and improved image uniformity than those obtained with conventional quadrature-type birdcage head coil.

Development of an ultrahigh-resolution Si-PM-based dual-head GAGG coincidence imaging system

Science.gov (United States)

Yamamoto, Seiichi; Watabe, Hiroshi; Kanai, Yasukazu; Kato, Katsuhiko; Hatazawa, Jun

2013-03-01

A silicon photomultiplier (Si-PM) is a promising photodetector for high resolution PET systems due to its small channel size and high gain. Using Si-PMs, it will be possible to develop a high resolution imaging systems. For this purpose, we developed a small field-of-view (FOV) ultrahigh-resolution Si-PM-based dual-head coincidence imaging system for small animals and plant research. A new scintillator, Ce doped Gd3Al12Ga3O12 (GAGG), was selected because of its high light output and its emission wavelength matched with the Si-PM arrays and contained no radioactivity. Each coincidence imaging block detector consists of 0.5×0.5×5 mm3 GAGG pixels combined with a 0.1-mm thick reflector to form a 20×17 matrix that was optically coupled to a Si-PM array (Hamamatsu MPPC S11064-050P) with a 1.5-mm thick light guide. The GAGG block size was 12.0×10.2 mm2. Two GAGG block detectors were positioned face to face and set on a flexible arm based detector stand. All 0.5 mm GAGG pixels in the block detectors were clearly resolved in the 2-dimensional position histogram. The energy resolution was 14.4% FWHM for the Cs-137 gamma ray. The spatial resolution was 0.7 mm FWHM measured using a 0.25 mm diameter Na-22 point source. Small animal and plant images were successfully obtained. We conclude that our developed ultrahigh-resolution Si-PM-based dual-head coincidence imaging system is promising for small animal and plant imaging research.

Ultrasonic phased array with surface acoustic wave for imaging cracks

Directory of Open Access Journals (Sweden)

Yoshikazu Ohara

2017-06-01

Full Text Available To accurately measure crack lengths, we developed a real-time surface imaging method (SAW PA combining an ultrasonic phased array (PA with a surface acoustic wave (SAW. SAW PA using a Rayleigh wave with a high sensitivity to surface defects was implemented for contact testing using a wedge with the third critical angle that allows the Rayleigh wave to be generated. Here, to realize high sensitivity imaging, SAW PA was optimized in terms of the wedge and the imaging area. The improved SAW PA was experimentally demonstrated using a fatigue crack specimen made of an aluminum alloy. For further verification in more realistic specimens, SAW PA was applied to stainless-steel specimens with a fatigue crack and stress corrosion cracks (SCCs. The fatigue crack was visualized with a high signal-to-noise ratio (SNR and its length was measured with a high accuracy of better than 1 mm. The SCCs generated in the heat-affected zones (HAZs of a weld were successfully visualized with a satisfactory SNR, although responses at coarse grains appeared throughout the imaging area. The SCC lengths were accurately measured. The imaging results also precisely showed complicated distributions of SCCs, which were in excellent agreement with the optically observed distributions.

Sensitivity of a multi-photomultiplier optical module for KM3NeT

NARCIS (Netherlands)

Löhner, H.; Mjos, A.

2009-01-01

For the KM3NeT neutrino telescope an optical module with a number of small photomultiplier tubes (multi-PMT optical module) will be advantageous for various reasons, e.g. reduced background rate, a larger number of coincidence hits, and sensitivity to ultra-high energy neutrinos. The properties of

Strategies for shortening the output pulse of silicon photomultipliers

OpenAIRE

Antoranz Canales, Pedro; Miranda Pantoja, José Miguel; Yebras Rivera, José Manuel

2012-01-01

In this work, three strategies for shortening the output pulse of a silicon photomultiplier (SiPM) are reported. The first strategy is passive filtering, where band-pass filtering removes the lowest frequency components in the signal, getting a noticeable reduction in pulse width (a compression ratio of 10: 1 was obtained). In the second place, a reflectometric scheme is proposed where the amplified signal coming from the SiPM is injected into a signal splitter with one of its stubs connected...

Thermal imager based on the array light sensor device of 128×128 CdHgTe-photodiodes

Directory of Open Access Journals (Sweden)

Reva V. P.

2010-08-01

Full Text Available The results of investigation of developed thermal imager for middle (3—5 µm infrared region are presented and its applications features are discussed. The thermal imager consists of cooled to 80 K 128×128 diodes focal plane array on the base of cadmium–mercury–telluride compound and cryostat with temperature checking system. The photodiode array is bonded with readout device (silicon focal processor via indium microcontacts. The measured average value of noise equivalent temperature difference was NETD= 20±4 mK (background radiation temperature T = 300 K, field of view 2θ = 180°, the cooled diaphragm was not used.

Methods for validating the presence of and characterizing proteins deposited onto an array

Science.gov (United States)

Schabacker, Daniel S.

2010-09-21

A method of determining if proteins have been transferred from liquid-phase protein fractions to an array comprising staining the array with a total protein stain and imaging the array, optionally comparing the staining with a standard curve generated by staining known amounts of a known protein on the same or a similar array; a method of characterizing proteins transferred from liquid-phase protein fractions to an array including staining the array with a post-translational modification-specific (PTM-specific) stain and imaging the array and, optionally, after staining the array with a PTM-specific stain and imaging the array, washing the array, re-staining the array with a total protein stain, imaging the array, and comparing the imaging with the PTM-specific stain with the imaging with the total protein stain; stained arrays; and images of stained arrays.

Front-end electronics and data acquisition system for imaging atmospheric Cherenkov telescopes

International Nuclear Information System (INIS)

Chen, Y.T.; La Taille, C. de; Suomijärvi, T.; Cao, Z.; Deligny, O.; Dulucq, F.; Ge, M.M.; Lhenry-Yvon, I.; Martin-Chassard, G.; Nguyen Trung, T.; Wanlin, E.; Xiao, G.; Yin, L.Q.; Yun Ky, B.; Zhang, L.; Zhang, H.Y.; Zhang, S.S.; Zhu, Z.

2015-01-01

In this paper, a front-end electronics based on an application-specific integrated circuit (ASIC) is presented for the future imaging atmospheric Cherenkov telescopes (IACTs). To achieve this purpose, a 16-channel ASIC chip, PARISROC 2 (Photomultiplier ARray Integrated in SiGe ReadOut Chip) is used in the analog signal processing and digitization. The digitized results are sent to the server by a user-defined User Datagram Protocol/Internet Protocol (UDP/IP) hardcore engine through Ethernet that is managed by a FPGA. A prototype electronics fulfilling the requirements of the Wide Field of View Cherenkov Telescope Array (WFCTA) of the Large High Altitude Air Shower Observatory (LHAASO) project has been designed, fabricated and tested to prove the concept of the design. A detailed description of the development with the results of the test measurements are presented. By using a new input structure and a new configuration of the ASIC, the dynamic range of the circuit is extended. A highly precise-time calibrating algorithm is also proposed, verified and optimized for the mass production. The test results suggest that the proposed electronics design fulfills the general specification of the future IACTs

Front-end electronics and data acquisition system for imaging atmospheric Cherenkov telescopes

Energy Technology Data Exchange (ETDEWEB)

Chen, Y.T., E-mail: chenytao@ynu.edu.cn [Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, 91406 Orsay Cedex (France); Yunnan University, 650091 Kunming (China); La Taille, C. de [OMEGA (UMS 3605) - IN2P3/CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France); Suomijärvi, T. [Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, 91406 Orsay Cedex (France); Cao, Z. [Institute of High Energy Physics, 100049 Beijing (China); Deligny, O. [Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, 91406 Orsay Cedex (France); Dulucq, F. [OMEGA (UMS 3605) - IN2P3/CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France); Ge, M.M. [Yunnan University, 650091 Kunming (China); Lhenry-Yvon, I. [Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, 91406 Orsay Cedex (France); Martin-Chassard, G. [OMEGA (UMS 3605) - IN2P3/CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France); Nguyen Trung, T.; Wanlin, E. [Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, 91406 Orsay Cedex (France); Xiao, G.; Yin, L.Q. [Institute of High Energy Physics, 100049 Beijing (China); Yun Ky, B. [Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, 91406 Orsay Cedex (France); Zhang, L. [Yunnan University, 650091 Kunming (China); Zhang, H.Y. [Tsinghua University, 100084 Beijing (China); Zhang, S.S.; Zhu, Z. [Institute of High Energy Physics, 100049 Beijing (China)

2015-09-21

In this paper, a front-end electronics based on an application-specific integrated circuit (ASIC) is presented for the future imaging atmospheric Cherenkov telescopes (IACTs). To achieve this purpose, a 16-channel ASIC chip, PARISROC 2 (Photomultiplier ARray Integrated in SiGe ReadOut Chip) is used in the analog signal processing and digitization. The digitized results are sent to the server by a user-defined User Datagram Protocol/Internet Protocol (UDP/IP) hardcore engine through Ethernet that is managed by a FPGA. A prototype electronics fulfilling the requirements of the Wide Field of View Cherenkov Telescope Array (WFCTA) of the Large High Altitude Air Shower Observatory (LHAASO) project has been designed, fabricated and tested to prove the concept of the design. A detailed description of the development with the results of the test measurements are presented. By using a new input structure and a new configuration of the ASIC, the dynamic range of the circuit is extended. A highly precise-time calibrating algorithm is also proposed, verified and optimized for the mass production. The test results suggest that the proposed electronics design fulfills the general specification of the future IACTs.

Sampling phased array, a new technique for ultrasonic signal processing and imaging now available to industry

OpenAIRE

Verkooijen, J.; Bulavinov, A.

2008-01-01

Over the past 10 years the improvement in the field of microelectronics and computer engineering has led to significant advances in ultrasonic signal processing and image construction techniques that are currently being applied to non-destructive material evaluation. A new phased array technique, called "Sampling Phased Array" has been developed in the Fraunhofer Institute for non-destructive testing [1]. It realizes a unique approach of measurement and processing of ultrasonic signals. The s...

Rearranging the lenslet array of the compact passive interference imaging system with high resolution

Science.gov (United States)

Liu, Gang; Wen, Desheng; Song, Zongxi

2017-10-01

With the development of aeronautics and astronautics, higher resolution requirement of the telescope was necessary. However, the increase in resolution of conventional telescope required larger apertures, whose size, weight and power consumption could be prohibitively expensive. This limited the further development of the telescope. This paper introduced a new imaging technology using interference—Compact Passive Interference Imaging Technology with High Resolution, and proposed a rearranging method for the arrangement of the lenslet array to obtain continuously object spatial frequency.

Digital electronics for 256 anode Hamamatsu H9500 PSPMT arrays in full-volume Compton imagers

International Nuclear Information System (INIS)

Harris, J T; Grudberg, P M; Warburton, W K

2014-01-01

Ziock et al.'s [1] recent Monte Carlo study of a proposed ''full-volume'' Compton Imaging Camera concluded that simultaneously locating a Compton scatter event's multiple interaction points within a single large scintillator crystal might be possible at 1 mm spatial resolution using a coded aperture mask sandwiched between two light guides and coupled to a position sensitive photomultiplier (PSPMT) to record the output light pattern. The method promises high efficiency at a relatively low cost. They are currently developing a lower resolution prototype using a large cubic scintillator (25.4 cm/side) whose masked face will be tiled with 25 Hamamatsu H9500 PSPMTs (6,400 outputs). XIA has contracted to develop and produce the readout electronics, which present several significant design challenges, including capturing all 6,400 anode outputs individually, with single photon sensitivity, in a compact format that will fit behind the tiled PSPMTs. 10,000 event/sec operation is desired, as is a cost of less than about $50/channel. In our approach, each PSPMT front end integrates the 256 anode signals and 8-1 multiplexes them to 32 differential outputs that are digitized in a PXI card using 4 octal 50 MHz ADCs. The multiplexers run at 8 MHz, sampling each anode at 1 MHz, which becomes the image frame rate. The ADC signals are demultiplexed and digitally filtered to extract the number of photons in each pixel in the full 2-D image. The design has been completed and built and is undergoing evaluation tests at the single PSPMT level

Actively-stabilized photomultiplier tube base for vacuum operation

International Nuclear Information System (INIS)

Bryan, M.A; Morris, C.L.; Idzorek, G.C.

1992-01-01

An actively stabilized photomultiplier tube (PMT) base design for an Amperex XP-2262B PMT is described. Positive-negative-positive transistors are used as low-impedance current sources to maintain constant voltages on the last three dynodes. This technique results in a highly stable, low-power tube base ideal for use with low-duty-factor beams, such as those found at the Clinton P. Anderson Meson Physics Facility. Furthermore, because of the low power usage of this large design, these bases can be sealed in a heat-conductive, electrically insulating material and used in a vacuum

Matrix phased array (MPA) imaging technology for resistance spot welds

Science.gov (United States)

Na, Jeong K.; Gleeson, Sean T.

2014-02-01

A three-dimensional MPA probe has been incorporated with a high speed phased array electronic board to visualize nugget images of resistance spot welds. The primary application area of this battery operated portable MPA ultrasonic imaging system is in the automotive industry which a conventional destructive testing process is commonly adopted to check the quality of resistance spot welds in auto bodies. Considering an average of five-thousand spot welds in a medium size passenger vehicle, the amount of time and effort given to popping the welds and measuring nugget size are immeasurable in addition to the millions of dollars' worth of scrap metals recycled per plant per year. This wasteful labor intensive destructive testing process has become less reliable as auto body sheet metal has transitioned from thick and heavy mild steels to thin and light high strength steels. Consequently, the necessity of developing a non-destructive inspection methodology has become inevitable. In this paper, the fundamental aspects of the current 3-D probe design, data acquisition algorithms, and weld nugget imaging process are discussed.

Matrix phased array (MPA) imaging technology for resistance spot welds

International Nuclear Information System (INIS)

Na, Jeong K.; Gleeson, Sean T.

2014-01-01

A three-dimensional MPA probe has been incorporated with a high speed phased array electronic board to visualize nugget images of resistance spot welds. The primary application area of this battery operated portable MPA ultrasonic imaging system is in the automotive industry which a conventional destructive testing process is commonly adopted to check the quality of resistance spot welds in auto bodies. Considering an average of five-thousand spot welds in a medium size passenger vehicle, the amount of time and effort given to popping the welds and measuring nugget size are immeasurable in addition to the millions of dollars' worth of scrap metals recycled per plant per year. This wasteful labor intensive destructive testing process has become less reliable as auto body sheet metal has transitioned from thick and heavy mild steels to thin and light high strength steels. Consequently, the necessity of developing a non-destructive inspection methodology has become inevitable. In this paper, the fundamental aspects of the current 3-D probe design, data acquisition algorithms, and weld nugget imaging process are discussed

Matrix phased array (MPA) imaging technology for resistance spot welds

Energy Technology Data Exchange (ETDEWEB)

Na, Jeong K.; Gleeson, Sean T. [Edison Welding Institute, 1250 Arthur E. Adams Drive, Columbus, OH 43221 (United States)

2014-02-18

A three-dimensional MPA probe has been incorporated with a high speed phased array electronic board to visualize nugget images of resistance spot welds. The primary application area of this battery operated portable MPA ultrasonic imaging system is in the automotive industry which a conventional destructive testing process is commonly adopted to check the quality of resistance spot welds in auto bodies. Considering an average of five-thousand spot welds in a medium size passenger vehicle, the amount of time and effort given to popping the welds and measuring nugget size are immeasurable in addition to the millions of dollars' worth of scrap metals recycled per plant per year. This wasteful labor intensive destructive testing process has become less reliable as auto body sheet metal has transitioned from thick and heavy mild steels to thin and light high strength steels. Consequently, the necessity of developing a non-destructive inspection methodology has become inevitable. In this paper, the fundamental aspects of the current 3-D probe design, data acquisition algorithms, and weld nugget imaging process are discussed.

Design and performance of single photon APD focal plane arrays for 3-D LADAR imaging

Science.gov (United States)

Itzler, Mark A.; Entwistle, Mark; Owens, Mark; Patel, Ketan; Jiang, Xudong; Slomkowski, Krystyna; Rangwala, Sabbir; Zalud, Peter F.; Senko, Tom; Tower, John; Ferraro, Joseph

2010-08-01

×We describe the design, fabrication, and performance of focal plane arrays (FPAs) for use in 3-D LADAR imaging applications requiring single photon sensitivity. These 32 × 32 FPAs provide high-efficiency single photon sensitivity for three-dimensional LADAR imaging applications at 1064 nm. Our GmAPD arrays are designed using a planarpassivated avalanche photodiode device platform with buried p-n junctions that has demonstrated excellent performance uniformity, operational stability, and long-term reliability. The core of the FPA is a chip stack formed by hybridizing the GmAPD photodiode array to a custom CMOS read-out integrated circuit (ROIC) and attaching a precision-aligned GaP microlens array (MLA) to the back-illuminated detector array. Each ROIC pixel includes an active quenching circuit governing Geiger-mode operation of the corresponding avalanche photodiode pixel as well as a pseudo-random counter to capture per-pixel time-of-flight timestamps in each frame. The FPA has been designed to operate at frame rates as high as 186 kHz for 2 μs range gates. Effective single photon detection efficiencies as high as 40% (including all optical transmission and MLA losses) are achieved for dark count rates below 20 kHz. For these planar-geometry diffused-junction GmAPDs, isolation trenches are used to reduce crosstalk due to hot carrier luminescence effects during avalanche events, and we present details of the crosstalk performance for different operating conditions. Direct measurement of temporal probability distribution functions due to cumulative timing uncertainties of the GmAPDs and ROIC circuitry has demonstrated a FWHM timing jitter as low as 265 ps (standard deviation is ~100 ps).

Monolithic array of 32 SPAD pixels for single-photon imaging at high frame rates

International Nuclear Information System (INIS)

Tisa, Simone; Guerrieri, Fabrizio; Zappa, Franco

2009-01-01

We present a single-chip monolithic array of 32 Single-Photon Avalanche Diodes (SPAD) and associated electronics for imaging at high frame rates and high sensitivity. Photodetectors, front-end circuitry and control electronics used to manage the array are monolithically integrated on the same chip in a standard 0.35 μm CMOS high-voltage technology. The array is composed of 32 'smart' pixels working in photon counting mode and functioning in a parallel fashion. Every cell comprises of an integrated SPAD photodetector, a novel quenching circuit named as Variable Load Quenching Circuit (VLQC), counting electronics and a buffer memory. Proper ancillary electronics that perform the arbitration of photon counts between two consecutive frames is integrated as well. Thanks to the presence of in-pixel memory registers, the inter-frame dead time between subsequent frames is limited to few nanoseconds. Since integration and download are performed simultaneously and the array can be addressed like a standard digital memory, the achievable maximum frame rate is very high in the order of hundreds of thousands of frame/s.

Automated flow quantification in valvular heart disease based on backscattered Doppler power analysis: implementation on matrix-array ultrasound imaging systems.

Science.gov (United States)

Buck, Thomas; Hwang, Shawn M; Plicht, Björn; Mucci, Ronald A; Hunold, Peter; Erbel, Raimund; Levine, Robert A

2008-06-01

Cardiac ultrasound imaging systems are limited in the noninvasive quantification of valvular regurgitation due to indirect measurements and inaccurate hemodynamic assumptions. We recently demonstrated that the principle of integration of backscattered acoustic Doppler power times velocity can be used for flow quantification in valvular regurgitation directly at the vena contracta of a regurgitant flow jet. We now aimed to accomplish implementation of automated Doppler power flow analysis software on a standard cardiac ultrasound system utilizing novel matrix-array transducer technology with detailed description of system requirements, components and software contributing to the system. This system based on a 3.5 MHz, matrix-array cardiac ultrasound scanner (Sonos 5500, Philips Medical Systems) was validated by means of comprehensive experimental signal generator trials, in vitro flow phantom trials and in vivo testing in 48 patients with mitral regurgitation of different severity and etiology using magnetic resonance imaging (MRI) for reference. All measurements displayed good correlation to the reference values, indicating successful implementation of automated Doppler power flow analysis on a matrix-array ultrasound imaging system. Systematic underestimation of effective regurgitant orifice areas >0.65 cm(2) and volumes >40 ml was found due to currently limited Doppler beam width that could be readily overcome by the use of new generation 2D matrix-array technology. Automated flow quantification in valvular heart disease based on backscattered Doppler power can be fully implemented on board a routinely used matrix-array ultrasound imaging systems. Such automated Doppler power flow analysis of valvular regurgitant flow directly, noninvasively, and user independent overcomes the practical limitations of current techniques.

TRitium Activity Measurements with a PhotomultipliEr in Liquids–The TRAMPEL experiment

International Nuclear Information System (INIS)

Priester, Florian; Klein, Manuel

2016-01-01

Highlights: • We have set up a new test device for measuring of tritiated water samples. • The device is very compact and easy and reliable in operation. • Easy integration in flow-through systems is possible. • The device has been operated at Tritium Laboratory Karlsruhe for several months. • The lower detection limit has been improved with regard to predecessors experiments. - Abstract: A common technique for the determination of the activity of tritiated water (HTO) is liquid scintillation counting (LSC). This implies sample taking, sample preparation and radioactive waste processing afterwards. When handling highly tritiated water special care has to be taken because of possible harmfulness of the sample. Furthermore, LSC devices are mostly large, heavy and expensive. The TRAMPEL experiment aims at measuring the activity of tritiated water in-line without sample taking. The device is intended to be easy to use and operate, quite inexpensive and compact. The measurement principle is based on electrons from β-decay which induce light in commercially available scintillation fibres. The light is detected by a small photomultiplier tube (PMT). A proof-of-principle was set up for static measurements using standard stainless steel parts. The complete device has a volume of less than 0.5 l.

TRitium Activity Measurements with a PhotomultipliEr in Liquids–The TRAMPEL experiment

Energy Technology Data Exchange (ETDEWEB)

Priester, Florian, E-mail: florian.priester@kit.edu; Klein, Manuel

2016-11-01

Highlights: • We have set up a new test device for measuring of tritiated water samples. • The device is very compact and easy and reliable in operation. • Easy integration in flow-through systems is possible. • The device has been operated at Tritium Laboratory Karlsruhe for several months. • The lower detection limit has been improved with regard to predecessors experiments. - Abstract: A common technique for the determination of the activity of tritiated water (HTO) is liquid scintillation counting (LSC). This implies sample taking, sample preparation and radioactive waste processing afterwards. When handling highly tritiated water special care has to be taken because of possible harmfulness of the sample. Furthermore, LSC devices are mostly large, heavy and expensive. The TRAMPEL experiment aims at measuring the activity of tritiated water in-line without sample taking. The device is intended to be easy to use and operate, quite inexpensive and compact. The measurement principle is based on electrons from β-decay which induce light in commercially available scintillation fibres. The light is detected by a small photomultiplier tube (PMT). A proof-of-principle was set up for static measurements using standard stainless steel parts. The complete device has a volume of less than 0.5 l.

Small-animal whole-body imaging using a photoacoustic full ring array system

Science.gov (United States)

Xia, Jun; Guo, Zijian; Aguirre, Andres; Zhu, Quing; Wang, Lihong V.

2011-03-01

In this report, we present a novel 3D photoacoustic computed tomography (PACT) system for small-animal whole-body imaging. The PACT system, based on a 512-element full-ring transducer array, received photoacoustic signals primarily from a 2-mm-thick slice. The light was generated by a pulse laser, and can either illuminate from the top or be reshaped to illuminate the sample from the side, using a conical lens and an optical condenser. The PACT system was capable of acquiring an in-plane image in 1.6 s; by scanning the sample in the elevational direction, a 3D tomographic image could be constructed. We tested the system by imaging a cylindrical phantom made of human hairs immersed in a scattering medium. The reconstructed image achieved an in-plane resolution of 0.1 mm and an elevational resolution of 1 mm. After deconvolution in the elevational direction, the 3D image was found to match well with the phantom. The system was also used to image a baby mouse in situ; the spinal cord and ribs can be seen easily in the reconstructed image. Our results demonstrate that the PACT system has the potential to be used for fast small-animal whole-body tomographic imaging.

Reconstructing 3D profiles of flux distribution in array of unshunted Josephson junctions from 2D scanning SQUID microscope images

International Nuclear Information System (INIS)

Nascimento, F.M.; Sergeenkov, S.; Araujo-Moreira, F.M.

2012-01-01

By using a specially designed algorithm (based on utilizing the so-called Hierarchical Data Format), we report on successful reconstruction of 3D profiles of local flux distribution within artificially prepared arrays of unshunted Nb-AlO x -Nb Josephson junctions from 2D surface images obtained via the scanning SQUID microscope. The analysis of the obtained results suggest that for large sweep areas, the local flux distribution significantly deviates from the conventional picture and exhibits a more complicated avalanche-type behavior with a prominent dendritic structure. -- Highlights: ► The penetration of external magnetic field into an array of Nb-AlO x -Nb Josephson junctions is studied. ► Using Scanning SQUID Microscope, 2D images of local flux distribution within array are obtained. ► Using specially designed pattern recognition algorithm, 3D flux profiles are reconstructed from 2D images.

Imaging subducted slabs using seismic arrays in the Western Pacific

Science.gov (United States)

Bentham, H. L.; Rost, S.

2010-12-01

In recent years array seismology has been used extensively to image the small scale structure of the Earth. Such structure likely represents chemical heterogeneity and is therefore essential in our understanding of mantle convection and the composition of the Earth’s deep interior. As subduction is the main source of (re)introducing slab material into the Earth, it is of particular interest to track these heterogeneities. Resolving details of the composition and deformation of subducted lithosphere can help provide constraints on the subduction process, the composition of the mantle and mantle convection. This study uses seismic array techniques to map seismic heterogeneities associated with western Pacfic subduction zones, where a variety of slab geometries have been previously observed. Seismic energy arriving prior to the PP arrival was analysed at Eielson Array (ILAR), Alaska. More than 200 earthquakes were selected with Mw ≥ 6 and with epicentral distances of 90-110deg, giving a good coverage of the PP precursor (P*P) wavefield. Initial findings indicate that the observed P*P arrive out of plane and are likely a result of scattering. These scatterers are linked to the subduction of the Pacific Plate under the Philippine Sea in the Izu-Bonin and Mariana subduction zones. To enable efficient processing of large datasets, a robust automatic coherent (but unpredicted) arrival detector algorithm has been developed to select suitable precursors. Slowness and backazimuth were calculated for each precursor and were used in conjunction with P*P arrival times to back-raytrace the energy from the array to the scatterer location. Processing of the full dataset will help refine models regarding slab deformation as they descend into the mantle as well as unveiling the depth of their descent.

Phosphor Scanner For Imaging X-Ray Diffraction

Science.gov (United States)

Carter, Daniel C.; Hecht, Diana L.; Witherow, William K.

1992-01-01

Improved optoelectronic scanning apparatus generates digitized image of x-ray image recorded in phosphor. Scanning fiber-optic probe supplies laser light stimulating luminescence in areas of phosphor exposed to x rays. Luminescence passes through probe and fiber to integrating sphere and photomultiplier. Sensitivity and resolution exceed previously available scanners. Intended for use in x-ray crystallography, medical radiography, and molecular biology.

Optimization of performance parameters for large area silicon photomultipliers for use in the GlueX experiment

Science.gov (United States)

Janzen, Kathryn Louise

Largely because of their resistance to magnetic fields, silicon photomultipliers (SiPMs) are being considered as the readout for the GlueX Barrel Calorimeter, a key component of the GlueX detector located immediately inside a 2.2 T superconducting solenoid. SiPMs with active area 1 x 1 mm2 have been investigated for use in other experiments, but detectors with larger active areas are required for the GlueX BCAL. This puts the GlueX collaboration in the unique position of being pioneers in the use of this frontend detection revolution by driving the technology for larger area sensors. SensL, a photonics research and development company in Ireland, has been collaborating with the University of Regina GlueX group to develop prototype large area SiPMs comprising 16 - 3x3 mm2 cells assembled in a close-packed matrix. Performance parameters of individual SensL 1x1 mm2 and 3x3 mm2 SiPMs along with prototype SensL SiPM arrays are tested, including current versus voltage characteristics, photon detection efficiency, and gain uniformity, in an effort to determine the suitability of these detectors to the GlueX BCAL readout.

X-ray detector array

International Nuclear Information System (INIS)

Houston, J.M.

1980-01-01

The object of the invention (an ionization chamber X-ray detector array for use with high speed computerised tomographic imaging apparatus) is to reduce the time required to produce a tomographic image. The detector array described determines the distribution of X-ray intensities in one or more flat, coplanar X-ray beams. It comprises three flat anode sheets parallel to the X-ray beam, a plurality of rod-like cathodes between the anodes, a detector gas between the electrodes and a means for applying a potential between the electrodes. Each of the X-ray sources is collimated to give a narrow, planar section of X-ray photons. Sets of X-ray sources in the array are pulsed simultaneously to obtain X-ray transmission data for tomographic image reconstruction. (U.K.)

Interference between PET and MRI sub-systems in a silicon-photomultiplier-based PET/MRI system

International Nuclear Information System (INIS)

Yamamoto, Seiichi; Watabe, Hiroshi; Kanai, Yasukazu; Hatazawa, Jun; Aoki, Masaaki; Sugiyama, Eiji; Watabe, Tadashi; Imaizumi, Masao; Shimosegawa, Eku

2011-01-01

The silicon-photomultiplier (Si-PM) is a promising photodetector, especially for integrated PET/MRI systems, due to its small size, high gain, and low sensitivity to static magnetic fields. The major problem using a Si-PM-based PET system within the MRI system is the interference between the PET and MRI units. We measured the interference by combining a Si-PM-based PET system with a permanent-magnet MRI system. When the RF signal-induced pulse height exceeded the lower energy threshold level of the PET system, interference between the Si-PM-based PET system and MRI system was detected. The prompt as well as the delayed coincidence count rates of the Si-PM-based PET system increased significantly. These noise counts produced severe artifacts on the reconstructed images of the Si-PM-based PET system. In terms of the effect of the Si-PM-based PET system on the MRI system, although no susceptibility artifact was observed on the MR images, electronic noise from the PET detector ring was detected by the RF coil and reduced the signal-to-noise ratio (S/N) of the MR images. The S/N degradation of the MR images was reduced when the distance between the RF coil and the Si-PM-based PET system was increased. We conclude that reducing the interference between the PET and MRI systems is essential for achieving the optimum performance of integrated Si-PM PET/MRI systems.

Comparison of polystyrene scintillator fiber array and monolithic polystyrene for neutron imaging and radiography

Energy Technology Data Exchange (ETDEWEB)

Simpson, R., E-mail: raspberry@lanl.gov; Cutler, T. E.; Danly, C. R.; Espy, M. A.; Goglio, J. H.; Hunter, J. F.; Madden, A. C.; Mayo, D. R.; Merrill, F. E.; Nelson, R. O.; Swift, A. L.; Wilde, C. H.; Zocco, T. G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2016-11-15

The neutron imaging diagnostic at the National Ignition Facility has been operating since 2011 generating neutron images of deuterium-tritium (DT) implosions at peak compression. The current design features a scintillating fiber array, which allows for high imaging resolution to discern small-scale structure within the implosion. In recent years, it has become clear that additional neutron imaging systems need to be constructed in order to provide 3D reconstructions of the DT source and these additional views need to be on a shorter line of sight. As a result, there has been increased effort to identify new image collection techniques that improve upon imaging resolution for these next generation neutron imaging systems, such as monolithic deuterated scintillators. This work details measurements performed at the Weapons Neutron Research Facility at Los Alamos National Laboratory that compares the radiographic abilities of the fiber scintillator with a monolithic scintillator, which may be featured in a future short line of sight neutron imaging systems.

Comparative study of new 130mm diameter fast photomultipliers for neutron detectors

International Nuclear Information System (INIS)

Moszynski, M.; Costa, G.J.; Guillaume, G.; Heusch, B.; Huck, A.; Mouatassim, S.

1991-01-01

The present paper is a summary of the test measurements carried out using new 130 mm diameter fast photomultiplier tubes manufactured by Philips (France), EMI (England) and Hamamatsu (Japan), along with a comparison to the results obtained with the well known XP 2041 Philips model. These tubes will be used in large size neutron detectors

Mapping Electrical Crosstalk in Pixelated Sensor Arrays

Science.gov (United States)

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

2017-01-01

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

Extending the dynamic range of silicon photomultipliers without increasing pixel count

International Nuclear Information System (INIS)

Johnson, Kurtis F.

2010-01-01

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

Short and long range gain monitoring of photomultipliers by means of a light pulser and an optical fibers bunch

International Nuclear Information System (INIS)

Besson, P.

1989-01-01

The gain monitoring of 8 XP3462 photomultipliers has been studied during a period of 3 months with a spark gap as a light pulser, an optical fibres bunch and 3 reference detectors. One of the reference PM is monitored thanks to a cristal of NaI irradiated by an 241 Am radioactive source, whereas the photodiode and its associated electronic is monitored thanks to a 57 Co source directly coupled to the junction. Two experimental methods have been tested. First the short term method consists in estimating several means of charge distributions and supposes the stability of different optical parameters like quantum efficiency or photoelectrons collection efficiency. The long term method consists in estimating several variances of charge distributions and supposes the validity, at first order, of photomultipliers' equations. In spite of unpropitious experimental conditions (tension switch off, no climatisation..), our results indicate that the short term method provides a precision of about 0.5% for the relative gain value but only during a short period which has been of 20 days. The long term method provides a precision of about 1.5% but is remained available during the 3 months of our experiment. This study has been developed for the new Neutrino oscillation program taking place near the Bugey nuclear plant and using 600 photomultipliers. The conclusions mentioned above are nevertheless valid for any particle detectors using photomultipliers [fr

Fast readout of scintillating fibres using position-sensitive photomultipliers

International Nuclear Information System (INIS)

Agoritsas, V.; Akchurin, N.; Bergdolt, A.M.; Bing, O.; Bravar, A.; Ditta, J.; Dufournaud, J.; Dyachenko, V.A.; Giacomich, R.; Gorin, A.M.; Kuroda, K.; Magaudda, D.; Newsom, C.; Okada, K.; Onel, Y.; Penzo, A.; Rakhmatov, V.Ye.; Rykalin, V.I.; Salvato, G.; Savin, A.A.; Schiavon, P.; Sillou, D.; Solovyov, Yu.A.; Takeutchi, F.; Tareb-Reyes, M.; Vasilchenko, V.G.; Yoshida, T.; Zaychenko, A.A.

1994-01-01

Major progress has recently been achieved in the fast readout of scintillating fibres using position-sensitive photomultipliers (PSPMs). Experimental results obtained with commercially available PSPMs already show a space resolution better than 200 μm, a time resolution of about 1.5 ns with a detection efficiency higher than 90%, and the possibility of separating double hits with a minimum distance of ∼3 mm. An upgrade of PSPMs based on new dynode structures is also in progress. Results obtained with one new PSPM prototype in a magnetic field are also presented. (orig.)

Photomultiplier pulse Read Out system for the preshower detector of the LHCb experiment

CERN Document Server

Ajaltouni, Ziad J; Cornat, R; Deschamps, O; Lecoq, J; Monteil, S; Perret, P

2003-01-01

The second generation experiment for CP violation studies in B decays, LHCb, is a 20-m-long single-arm spectrometer to be installed on the future Large Hadron Collider at CERN. For its precision measurement purpose, it combines precise vertex location and particle identification, in addition to a performance trigger system able to cope with high flux. The first level of trigger is mainly based on the fast response of the calorimetric subsystem. Of major importance is the 6000 channels preshower detector that aims to validate the electromagnetic nature of calorimetric showers. It consists of two- radiation-length lead sheet in front of a scintillator plane. Scintillator signals are extracted from plastic cells using wavelength-shifting fibres coupled to multi-anode photomultiplier tubes. The preshower Read Out system has to cope with fluctuating photomultiplier pulses caused by small amounts of photoelectrons, in addition to strong constraints imposed by the 40 MHz LHC bunch- crossing frequency. A special Read...

Infrared laser transillumination CT imaging system using parallel fiber arrays and optical switches for finger joint imaging

Science.gov (United States)

Sasaki, Yoshiaki; Emori, Ryota; Inage, Hiroki; Goto, Masaki; Takahashi, Ryo; Yuasa, Tetsuya; Taniguchi, Hiroshi; Devaraj, Balasigamani; Akatsuka, Takao

2004-05-01

The heterodyne detection technique, on which the coherent detection imaging (CDI) method founds, can discriminate and select very weak, highly directional forward scattered, and coherence retaining photons that emerge from scattering media in spite of their complex and highly scattering nature. That property enables us to reconstruct tomographic images using the same reconstruction technique as that of X-Ray CT, i.e., the filtered backprojection method. Our group had so far developed a transillumination laser CT imaging method based on the CDI method in the visible and near-infrared regions and reconstruction from projections, and reported a variety of tomographic images both in vitro and in vivo of biological objects to demonstrate the effectiveness to biomedical use. Since the previous system was not optimized, it took several hours to obtain a single image. For a practical use, we developed a prototype CDI-based imaging system using parallel fiber array and optical switches to reduce the measurement time significantly. Here, we describe a prototype transillumination laser CT imaging system using fiber-optic based on optical heterodyne detection for early diagnosis of rheumatoid arthritis (RA), by demonstrating the tomographic imaging of acrylic phantom as well as the fundamental imaging properties. We expect that further refinements of the fiber-optic-based laser CT imaging system could lead to a novel and practical diagnostic tool for rheumatoid arthritis and other joint- and bone-related diseases in human finger.

An Educational Kit Based On a Modular Silicon Photomultiplier System

International Nuclear Information System (INIS)

Caccia, Massimo; Chmill, Valery; Ebolese, Amedeo; Martemyanov, Alexander; Risigo, Fabio; Santoro, Romualdo; Locatelli, Marco; Pieracci, Maura; Tintori, Carlo

2013-06-01

Silicon Photo-Multipliers (SiPM) are state of the art light detectors with unprecedented single photon sensitivity and photon number resolving capability, representing a breakthrough in several fundamental and applied Science domains. An educational experiment based on a SiPM set-up is proposed in this article, guiding the student towards a comprehensive knowledge of this sensor technology while experiencing the quantum nature of light and exploring the statistical properties of the light pulses emitted by a LED. (authors)

The Belle II imaging Time-of-Propagation (iTOP) detector

Science.gov (United States)

Fast, J.; Belle II Barrel Particle Identification Group

2017-12-01

High precision flavor physics measurements are an essential complement to the direct searches for new physics at the LHC ATLAS and CMS experiments. Such measurements will be performed using the upgraded Belle II detector that will take data at the SuperKEKB accelerator. With 40x the luminosity of KEKB, the detector systems must operate efficiently at much higher rates than the original Belle detector. A central element of the upgrade is the barrel particle identification system. Belle II has built and installed an imaging-Time-of-Propagation (iTOP) detector. The iTOP uses quartz optics as Cherenkov radiators. The photons are transported down the quartz bars via total internal reflection with a spherical mirror at the forward end to reflect photons to the backward end where they are imaged onto an array of segmented Micro-Channel Plate Photo-Multiplier Tubes (MCP-PMTs). The system is read out using giga-samples per second waveform sampling Application-Specific Integrated Circuits (ASICs). The combined timing and spatial distribution of the photons for each event are used to determine particle species. This paper provides an overview of the iTOP system.

A transmit/receive radiofrequency array for imaging the carotid arteries at 7 Tesla: coil design and first in vivo results.

Science.gov (United States)

Kraff, Oliver; Bitz, Andreas K; Breyer, Tobias; Kruszona, Stefan; Maderwald, Stefan; Brote, Irina; Gizewski, Elke R; Ladd, Mark E; Quick, Harald H

2011-04-01

To develop a transmit/receive radiofrequency (RF) array for magnetic resonance imaging (MRI) of the carotid arteries at 7 T. The prototype is characterized in numerical simulations and bench measurements, and the feasibility of plaque imaging at 7 T is demonstrated in first in vivo images. The RF phased array coil consists of 8 surface loop coils. To allow imaging of both sides of the neck, the RF array is divided into 2 coil clusters, each with 4 overlapping loop elements. For safety validation, numerical computations of the RF field distribution and the corresponding specific absorption rate were performed on the basis of a heterogeneous human body model. To validate the coil model, maps of the transmit B1(+) field were compared between simulation and measurement. In vivo images of a healthy volunteer and a patient (ulcerating plaque and a 50% stenosis of the right internal carotid artery) were acquired using a 3-dimensional FLASH sequence with a high isotropic spatial resolution of 0.54 mm as well as using pulse-triggered proton density (PD)/T2-weighted turbo spin echo sequences. Measurements of the S-parameters yielded a reflection and isolation of the coil elements of better than -18 and -13 dB, respectively. Measurements of the g-factor indicated good image quality for parallel imaging acceleration factors up to 2.4. A similar distribution and a very good match of the absolute values were found between the measured and simulated B1(+) transmit RF field for the validation of the coil model. In vivo images revealed good signal excitation of both sides of the neck and a high vessel-to-background image contrast for the noncontrast-enhanced 3-dimensional FLASH sequence. Imaging at 7 T could depict the extent of stenosis, and revealed the disruption and ulcer of the plaque. This study demonstrates that 2 four-channel transmit/receive RF arrays for each side of the neck is a suitable concept for in vivo MRI of the carotid arteries at 7 Tesla. Further studies are

Development of a 400 Level 3C Clamped Downhole Seismic Receiver Array for 3D Borehole Seismic Imaging of Gas Reservoirs

Energy Technology Data Exchange (ETDEWEB)

Bjorn N. P. Paulsson

2006-09-30

Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to perform high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology has been hampered by the lack of acquisition technology necessary to record large volumes of high frequency, high signal-to-noise-ratio borehole seismic data. This project took aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array has removed the technical acquisition barrier for recording the data volumes necessary to do high resolution 3D VSP and 3D cross-well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that promise to take the gas industry to the next level in their quest for higher resolution images of deep and complex oil and gas reservoirs. Today only a fraction of the oil or gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of detailed compartmentalization of oil and gas reservoirs. In this project, we developed a 400 level 3C borehole seismic receiver array that allows for economic use of 3D borehole seismic imaging for reservoir characterization and monitoring. This new array has significantly increased the efficiency of recording large data volumes at sufficiently dense spatial sampling to resolve reservoir complexities. The receiver pods have been fabricated and tested to withstand high temperature (200 C/400 F) and high pressure (25,000 psi), so that they can operate in wells up to 7,620 meters (25,000 feet) deep. The receiver array is deployed on standard production or drill tubing. In combination with 3C surface seismic or 3C borehole seismic sources, the 400

A Novel 3D Imaging Method for Airborne Downward-Looking Sparse Array SAR Based on Special Squint Model

Directory of Open Access Journals (Sweden)

Xiaozhen Ren

2014-01-01

Full Text Available Three-dimensional (3D imaging technology based on antenna array is one of the most important 3D synthetic aperture radar (SAR high resolution imaging modes. In this paper, a novel 3D imaging method is proposed for airborne down-looking sparse array SAR based on the imaging geometry and the characteristic of echo signal. The key point of the proposed algorithm is the introduction of a special squint model in cross track processing to obtain accurate focusing. In this special squint model, point targets with different cross track positions have different squint angles at the same range resolution cell, which is different from the conventional squint SAR. However, after theory analysis and formulation deduction, the imaging procedure can be processed with the uniform reference function, and the phase compensation factors and algorithm realization procedure are demonstrated in detail. As the method requires only Fourier transform and multiplications and thus avoids interpolations, it is computationally efficient. Simulations with point scatterers are used to validate the method.

Stability and behavior of the outer array of small water Cherenkov detectors, outriggers, in the HAWC observatory

OpenAIRE

Capistrán, T.; Torres, I.; Moreno, E.; collaboration, for the HAWC

2017-01-01

The High-Altitude Water Cherenkov (HAWC) Observatory is used for detecting TeV gamma rays. HAWC is operating at 4,100 meters above level sea on the slope of the Sierra Negra Volcano in the State of Puebla, Mexico, and consists of an array of 300 water Cherenkov detectors (WCDs) covering an area of 22,000 $m^2$. Each WCD is equipped with four photomultiplier tubes (PMTs) to detect Cherenkov emission in the water from secondary particles of extensive air-shower (EAS) that are produced in the in...

Characterization of the 10-stages R5900 Hamamatsu photomultipliers for the hadronic ATLAS calorimeter

International Nuclear Information System (INIS)

Montarou, G.; Bouhemaid, N.; Grenier, Ph.; Crouau, M.; Muanza, G.S.; Poirot, S.; Vazeille, F.; Gil Botella, I.; Hoz, S.G. de la

1997-01-01

The measurements carried out, at Clermont on the R5900 Hamamatsu photomultipliers for the ATLAS hadronic calorimeter are summarised. The TILECAL specifications are given. Amplification measurements, dark current measurements, linearity, magnetic sensitivity and the voltage divider optimisation are presented. (K.A.)

High resolution phoswich gamma-ray imager utilizing monolithic MPPC arrays with submillimeter pixelized crystals

International Nuclear Information System (INIS)

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

2013-01-01

We report the development of a high spatial resolution tweezers-type coincidence gamma-ray camera for medical imaging. This application consists of large-area monolithic Multi-Pixel Photon Counters (MPPCs) and submillimeter pixelized scintillator matrices. The MPPC array has 4 × 4 channels with a three-side buttable, very compact package. For typical operational gain of 7.5 × 10 5 at + 20 °C, gain fluctuation over the entire MPPC device is only ± 5.6%, and dark count rates (as measured at the 1 p.e. level) amount to ≤ 400 kcps per channel. We selected Ce-doped (Lu,Y) 2 (SiO 4 )O (Ce:LYSO) and a brand-new scintillator, Ce-doped Gd 3 Al 2 Ga 3 O 12 (Ce:GAGG) due to their high light yield and density. To improve the spatial resolution, these scintillators were fabricated into 15 × 15 matrices of 0.5 × 0.5 mm 2 pixels. The Ce:LYSO and Ce:GAGG scintillator matrices were assembled into phosphor sandwich (phoswich) detectors, and then coupled to the MPPC array along with an acrylic light guide measuring 1 mm thick, and with summing operational amplifiers that compile the signals into four position-encoded analog outputs being used for signal readout. Spatial resolution of 1.1 mm was achieved with the coincidence imaging system using a 22 Na point source. These results suggest that the gamma-ray imagers offer excellent potential for applications in high spatial medical imaging.

An Ultra-High Element Density pMUT Array with Low Crosstalk for 3-D Medical Imaging

Directory of Open Access Journals (Sweden)

Tian-Ling Ren

2013-07-01

Full Text Available A ~1 MHz piezoelectric micromachined ultrasonic transducer (pMUT array with ultra-high element density and low crosstalk is proposed for the first time. This novel pMUT array is based on a nano-layer spin-coating lead zirconium titanium film technique and can be fabricated with high element density using a relatively simple process. Accordingly, key fabrication processes such as thick piezoelectric film deposition, low-stress Si-SOI bonding and bulk silicon removal have been successfully developed. The novel fine-pitch 6 × 6 pMUT arrays can all work at the desired frequency (~1 MHz with good uniformity, high performance and potential IC integration compatibility. The minimum interspace is ~20 μm, the smallest that has ever been achieved to the best of our knowledge. These arrays can be potentially used to steer ultrasound beams and implement high quality 3-D medical imaging applications.

Sparse acoustic imaging with a spherical array

DEFF Research Database (Denmark)

Fernandez Grande, Efren; Xenaki, Angeliki

2015-01-01

In recent years, a number of methods for sound source localization and sound field reconstruction with spherical microphone arrays have been proposed. These arrays have properties that are potentially very useful, e.g. omni-directionality, robustness, compensable scattering, etc. This paper propo...

Coded aperture imaging: the modulation transfer function for uniformly redundant arrays

International Nuclear Information System (INIS)

Fenimore, E.E.

1980-01-01

Coded aperture imaging uses many pinholes to increase the SNR for intrinsically weak sources when the radiation can be neither reflected nor refracted. Effectively, the signal is multiplexed onto an image and then decoded, often by a computer, to form a reconstructed image. We derive the modulation transfer function (MTF) of such a system employing uniformly redundant arrays (URA). We show that the MTF of a URA system is virtually the same as the MTF of an individual pinhole regardless of the shape or size of the pinhole. Thus, only the location of the pinholes is important for optimum multiplexing and decoding. The shape and size of the pinholes can then be selected based on other criteria. For example, one can generate self-supporting patterns, useful for energies typically encountered in the imaging of laser-driven compressions or in soft x-ray astronomy. Such patterns contain holes that are all the same size, easing the etching or plating fabrication efforts for the apertures. A new reconstruction method is introduced called delta decoding. It improves the resolution capabilities of a coded aperture system by mitigating a blur often introduced during the reconstruction step

An LTCC Based Compact SIW Antenna Array Feed Network for a Passive Imaging Radiometer

KAUST Repository

Abuzaid, Hattan

2013-02-05

Passive millimeter-wave (PMMW) imaging is a technique that allows the detection of inherent millimeter-wave radiation emitted by bodies. Since different bodies with varying properties emit unequal power intensities, a contrast can be established to detect their presence. The advantage of this imaging scheme over other techniques, such as optical and infrared imaging, is its ability to operate under all weather conditions. This is because the relatively long wavelengths of millimeter-waves, as compared to visible light, penetrate through clouds, fog, and sandstorms. The core of a PMMW camera is an antenna, which receives the electromagnetic radiation from a scene. Because PMMW systems require high gains to operate, large antenna arrays are typically employed. This mandatory increase of antenna elements is associated with a large feeding network. Therefore, PMMW cameras usually have a big profile. In this work, two enabling technologies, namely, Substrate integrated Waveguide (SIW) and Low Temperature Co-fired Ceramic (LTCC), are coupled with an innovative design to miniaturize the passive front-end. The two technologies synergize very well with the shielded characteristics of SIW and the high density multilayer integration of LTCC. The proposed design involves a novel multilayer power divider, which is incorporated in a folded feed network structure by moving between layers. The end result is an efficient feeding network, which footprint is least affected by an increase in array size. This is because the addition of more elements is accommodated by a vertical expansion rather than a lateral one. To characterize the feed network, an antenna array has been designed and integrated through efficient transitions.The complete structure has been simulated and fabricated. The results demonstrate an excellent performance, manifesting in a gain of 20 dBi and a bandwidth of more than 11.4% at 35 GHz. These values satisfy the general requirements of a PMMW system.

Silicon Photo-Multiplier Radiation Hardness Tests with a White Neutron Beam

International Nuclear Information System (INIS)

Montanari, A.; Tosi, N.; Pietropaolo, A.; Andreotti, M.; Baldini, W.; Calabrese, R.; Cibinetto, G.; Luppi, E.; Cotta Ramusino, A.; Malaguti, R.; Santoro, V.; Tellarini, G.; Tomassetti, L.; De Donato, C.; Reali, E.

2013-06-01

We report radiation hardness tests performed, with a white neutron beam, at the Geel Electron Linear Accelerator in Belgium on silicon Photo-Multipliers. These are semiconductor photon detectors made of a square matrix of Geiger-Mode Avalanche photo-diodes on a silicon substrate. Several samples from different manufacturers have been irradiated integrating up to about 6.2 x 10 9 1-MeV-equivalent neutrons per cm 2 . (authors)

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

Science.gov (United States)

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

Silicon photomultiplier's gain stabilization by bias correction for compensation of the temperature fluctuations

International Nuclear Information System (INIS)

Dorosz, P.; Baszczyk, M.; Glab, S.; Kucewicz, W.; Mik, L.; Sapor, M.

2013-01-01

Gain of the silicon photomultiplier is strongly dependent on the value of bias voltage and temperature. This paper proposes a method for gain stabilization just by compensation of temperature fluctuations by bias correction. It has been confirmed that this approach gives good results and the gain can be kept very stable

Comparison of optimised endovaginal vs external array coil T2-weighted and diffusion-weighted imaging techniques for detecting suspected early stage (IA/IB1) uterine cervical cancer

Energy Technology Data Exchange (ETDEWEB)

Downey, Kate; Morgan, Veronica A.; Giles, Sharon L.; MacDonald, A.; DeSouza, Nandita M. [The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, CRUK Cancer Imaging Centre, Surrey (United Kingdom); Attygalle, Ayoma D. [The Royal Marsden NHS Foundation Trust, Department of Histopathology, London (United Kingdom); Davis, M. [Kingston Hospital, Department of Gynaecology, Kingston-upon-Thames, Surrey (United Kingdom); Ind, Thomas E.J.; Shepherd, John H. [The Royal Marsden NHS Foundation Trust, Gynecology Unit, London (United Kingdom)

2016-04-15

To compare sensitivity and specificity of endovaginal versus external-array coil T2-W and T2-W + DWI for detecting and staging small cervical tumours. Optimised endovaginal and external array coil MRI at 3.0-T was done prospectively in 48 consecutive patients with stage Ia/Ib1 cervical cancer. Sensitivity/specificity for detecting tumour and parametrial extension against histopathology for a reading radiologist were determined on coronal T2-W and T2W + DW images. An independent radiologist also scored T2-W images without and with addition of DWI for the external-array and endovaginal coils on separate occasions >2 weeks apart. Cohen's kappa assessed inter- and intra-observer agreement. Median tumour volume in 19/38 cases positive on subsequent histology was 1.75 cm{sup 3}. Sensitivity, specificity, PPV, NPV were: reading radiologist 91.3 %, 89.5 %, 91.3 %, 89.5 %, respectively; independent radiologist T2-W 82.6 %, 73.7 %, 79.1 %, 77.8 % for endovaginal, 73.9 %, 89.5 %, 89.5 %, 73.9 % for external-array coil. Adding DWI improved sensitivity and specificity of endovaginal imaging (78.2 %, 89.5 %); adding DWI to external-array imaging improved specificity (94.7 %) but reduced sensitivity (66.7 %). Inter- and intra-observer agreement on T2-W + DWI was good (kappa = 0.67 and 0.62, respectively). Endovaginal coil T2-W MRI is more sensitive than external-array coil for detecting tumours <2 cm{sup 3}; adding DWI improves specificity of endovaginal imaging but reduces sensitivity of external-array imaging. (orig.)

Study of a photomultiplier for the measurement of low light flows by photon counting

International Nuclear Information System (INIS)

Haye, Kleber

1964-01-01

After a recall of the history of the discovery and use of the photoemission effect, a presentation of the main characteristics of photomultipliers, a discussion of performance and weaknesses of electron multiplier-based cells, this research thesis addresses the study of low light flows. The author tried to determine whether it was possible, at ambient temperature, to reduce the influence of the thermoelectric effect. In order to do so, he made a detailed study of the amplitude spectrum of pulses of photoelectric origin. In order to analyse the influence of temperature of photomultiplier characteristics, he studied, with respect to temperature, the variation of the counting rate corresponding to darkness, the variation of pulse amplitude spectrum, and relative variations of the quantum efficiency for various wavelengths. In parallel with the study by counting, a study has been performed by using the well known mean current measurement [fr

In vivo sensitivity estimation and imaging acceleration with rotating RF coil arrays at 7 Tesla

Science.gov (United States)

Li, Mingyan; Jin, Jin; Zuo, Zhentao; Liu, Feng; Trakic, Adnan; Weber, Ewald; Zhuo, Yan; Xue, Rong; Crozier, Stuart

2015-03-01

Using a new rotating SENSitivity Encoding (rotating-SENSE) algorithm, we have successfully demonstrated that the rotating radiofrequency coil array (RRFCA) was capable of achieving a significant reduction in scan time and a uniform image reconstruction for a homogeneous phantom at 7 Tesla. However, at 7 Tesla the in vivo sensitivity profiles (B1-) become distinct at various angular positions. Therefore, sensitivity maps at other angular positions cannot be obtained by numerically rotating the acquired ones. In this work, a novel sensitivity estimation method for the RRFCA was developed and validated with human brain imaging. This method employed a library database and registration techniques to estimate coil sensitivity at an arbitrary angular position. The estimated sensitivity maps were then compared to the acquired sensitivity maps. The results indicate that the proposed method is capable of accurately estimating both magnitude and phase of sensitivity at an arbitrary angular position, which enables us to employ the rotating-SENSE algorithm to accelerate acquisition and reconstruct image. Compared to a stationary coil array with the same number of coil elements, the RRFCA was able to reconstruct images with better quality at a high reduction factor. It is hoped that the proposed rotation-dependent sensitivity estimation algorithm and the acceleration ability of the RRFCA will be particularly useful for ultra high field MRI.

In vivo sensitivity estimation and imaging acceleration with rotating RF coil arrays at 7 Tesla.

Science.gov (United States)

Li, Mingyan; Jin, Jin; Zuo, Zhentao; Liu, Feng; Trakic, Adnan; Weber, Ewald; Zhuo, Yan; Xue, Rong; Crozier, Stuart

2015-03-01

Using a new rotating SENSitivity Encoding (rotating-SENSE) algorithm, we have successfully demonstrated that the rotating radiofrequency coil array (RRFCA) was capable of achieving a significant reduction in scan time and a uniform image reconstruction for a homogeneous phantom at 7 Tesla. However, at 7 Tesla the in vivo sensitivity profiles (B1(-)) become distinct at various angular positions. Therefore, sensitivity maps at other angular positions cannot be obtained by numerically rotating the acquired ones. In this work, a novel sensitivity estimation method for the RRFCA was developed and validated with human brain imaging. This method employed a library database and registration techniques to estimate coil sensitivity at an arbitrary angular position. The estimated sensitivity maps were then compared to the acquired sensitivity maps. The results indicate that the proposed method is capable of accurately estimating both magnitude and phase of sensitivity at an arbitrary angular position, which enables us to employ the rotating-SENSE algorithm to accelerate acquisition and reconstruct image. Compared to a stationary coil array with the same number of coil elements, the RRFCA was able to reconstruct images with better quality at a high reduction factor. It is hoped that the proposed rotation-dependent sensitivity estimation algorithm and the acceleration ability of the RRFCA will be particularly useful for ultra high field MRI. Copyright © 2014 Elsevier Inc. All rights reserved.

Research of Infrared Imaging at Atmospheric Pressure Using a Substrate-Free Focal Plane Array

International Nuclear Information System (INIS)

Wu Jian-Xiong; Cheng Teng; Zhang Qing-Chuan; Zhang Yong; Mao Liang; Gao Jie; Wu Xiao-Ping; Chen Da-Peng

2013-01-01

An equivalent circuit model to the substrate-free focal plane array (FPA) is established. Using this fast and effective model, the performance of infrared (IR) imaging at atmospheric pressure is investigated and it is found that the substrate-free FPA has the ability of IR imaging at atmospheric pressure, whereas it has a slightly degraded noise equivalent temperature difference (NETD) as compared with IR imaging under a high vacuum. This feature is also identified experimentally by a substrate-free FPA with pixel size of 50 × 50 μm 2 . The NETDs are measured to be 160 mK at 10 −2 Pa pressure and 1.08 K at atmospheric pressure

Dual-Polarization, Multi-Frequency Antenna Array for use with Hurricane Imaging Radiometer

Science.gov (United States)

Little, John

2013-01-01

Advancements in common aperture antenna technology were employed to utilize its proprietary genetic algorithmbased modeling tools in an effort to develop, build, and test a dual-polarization array for Hurricane Imaging Radiometer (HIRAD) applications. Final program results demonstrate the ability to achieve a lightweight, thin, higher-gain aperture that covers the desired spectral band. NASA employs various passive microwave and millimeter-wave instruments, such as spectral radiometers, for a range of remote sensing applications, from measurements of the Earth's surface and atmosphere, to cosmic background emission. These instruments such as the HIRAD, SFMR (Stepped Frequency Microwave Radiometer), and LRR (Lightweight Rainfall Radiometer), provide unique data accumulation capabilities for observing sea surface wind, temperature, and rainfall, and significantly enhance the understanding and predictability of hurricane intensity. These microwave instruments require extremely efficient wideband or multiband antennas in order to conserve space on the airborne platform. In addition, the thickness and weight of the antenna arrays is of paramount importance in reducing platform drag, permitting greater time on station. Current sensors are often heavy, single- polarization, or limited in frequency coverage. The ideal wideband antenna will have reduced size, weight, and profile (a conformal construct) without sacrificing optimum performance. The technology applied to this new HIRAD array will allow NASA, NOAA, and other users to gather information related to hurricanes and other tropical storms more cost effectively without sacrificing sensor performance or the aircraft time on station. The results of the initial analysis and numerical design indicated strong potential for an antenna array that would satisfy all of the design requirements for a replacement HIRAD array. Multiple common aperture antenna methodologies were employed to achieve exceptional gain over the entire

Cell membrane conformation at vertical nanowire array interface revealed by fluorescence imaging

International Nuclear Information System (INIS)

Berthing, Trine; Bonde, Sara; Rostgaard, Katrine R; Martinez, Karen L; Madsen, Morten Hannibal; Sørensen, Claus B; Nygård, Jesper

2012-01-01

The perspectives offered by vertical arrays of nanowires for biosensing applications in living cells depend on the access of individual nanowires to the cell interior. Recent results on electrical access and molecular delivery suggest that direct access is not always obtained. Here, we present a generic approach to directly visualize the membrane conformation of living cells interfaced with nanowire arrays, with single nanowire resolution. The method combines confocal z-stack imaging with an optimized cell membrane labelling strategy which was applied to HEK293 cells interfaced with 2–11 μm long and 3–7 μm spaced nanowires with various surface coatings (bare, aminosilane-coated or polyethyleneimine-coated indium arsenide). We demonstrate that, for all commonly used nanowire lengths, spacings and surface coatings, nanowires generally remain enclosed in a membrane compartment, and are thereby not in direct contact with the cell interior. (paper)

Development of high performance readout ASICs for silicon photomultipliers (SiPMs)

International Nuclear Information System (INIS)

Shen, Wei

2012-01-01

Silicon Photomultipliers (SiPMs) are novel kind of solid state photon detectors with extremely high photon detection resolution. They are composed of hundreds or thousands of avalanche photon diode pixels connected in parallel. These avalanche photon diodes are operated in Geiger Mode. SiPMs have the same magnitude of multiplication gain compared to the conventional photomultipliers (PMTs). Moreover, they have a lot of advantages such as compactness, relatively low bias voltage and magnetic field immunity etc. Special readout electronics are required to preserve the high performance of the detector. KLauS and STiC are two CMOS ASIC chips designed in particular for SiPMs. KLauS is used for SiPM charge readout applications. Since SiPMs have a much larger detector capacitance compared to other solid state photon detectors such as PIN diodes and APDs, a few special techniques are used inside the chip to make sure a descent signal to noise ratio for pixel charge signal can be obtained. STiC is a chip dedicated to SiPM time-of-flight applications. High bandwidth and low jitter design schemes are mandatory for such applications where time jitter less than tens of picoseconds is required. Design schemes and error analysis as well as measurement results are presented in the thesis.

CCD and IR array controllers

Science.gov (United States)

Leach, Robert W.; Low, Frank J.

2000-08-01

A family of controllers has bene developed that is powerful and flexible enough to operate a wide range of CCD and IR focal plane arrays in a variety of ground-based applications. These include fast readout of small CCD and IR arrays for adaptive optics applications, slow readout of large CCD and IR mosaics, and single CCD and IR array operation at low background/low noise regimes as well as high background/high speed regimes. The CCD and IR controllers have a common digital core based on user- programmable digital signal processors that are used to generate the array clocking and signal processing signals customized for each application. A fiber optic link passes image data and commands to VME or PCI interface boards resident in a host computer to the controller. CCD signal processing is done with a dual slope integrator operating at speeds of up to one Megapixel per second per channel. Signal processing of IR arrays is done either with a dual channel video processor or a four channel video processor that has built-in image memory and a coadder to 32-bit precision for operating high background arrays. Recent developments underway include the implementation of a fast fiber optic data link operating at a speed of 12.5 Megapixels per second for fast image transfer from the controller to the host computer, and supporting image acquisition software and device drivers for the PCI interface board for the Sun Solaris, Linux and Windows 2000 operating systems.

Operating scheme for the light-emitting diode array of a volumetric display that exhibits multiple full-color dynamic images

Science.gov (United States)

Hirayama, Ryuji; Shiraki, Atsushi; Nakayama, Hirotaka; Kakue, Takashi; Shimobaba, Tomoyoshi; Ito, Tomoyoshi

2017-07-01

We designed and developed a control circuit for a three-dimensional (3-D) light-emitting diode (LED) array to be used in volumetric displays exhibiting full-color dynamic 3-D images. The circuit was implemented on a field-programmable gate array; therefore, pulse-width modulation, which requires high-speed processing, could be operated in real time. We experimentally evaluated the developed system by measuring the luminance of an LED with varying input and confirmed that the system works appropriately. In addition, we demonstrated that the volumetric display exhibits different full-color dynamic two-dimensional images in two orthogonal directions. Each of the exhibited images could be obtained only from the prescribed viewpoint. Such directional characteristics of the system are beneficial for applications, including digital signage, security systems, art, and amusement.