The Experts below are selected from a list of 237816 Experts worldwide ranked by ideXlab platform
Katsuji Koyama - One of the best experts on this subject based on the ideXlab platform.
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x ray Imaging spectrometer xis on board suzaku
Publications of the Astronomical Society of Japan, 2007Co-Authors: Katsuji Koyama, Kiyoshi Hayashida, H Tsunemi, Tadayasu Dotani, Mark W Bautz, Takeshi Go Tsuru, Hironori Matsumoto, Y Ogawara, G Ricker, J DotyAbstract:The XIS is an X-Ray Imaging Spectrometer system, consisting of state-of-the-art charge-coupled devices (CCDs) optimized for X-Ray detection, camera bodies, and control electronics. Four sets of XIS sensors are placed at the focal planes of the grazing-incidence, nested thin-foil mirrors (XRT: X-Ray Telescope) onboard the Suzaku satellite. Three of the XIS sensors have front-illuminated CCDs, while the other has a back-illuminated CCD. Coupled with the XRT, the energy range of 0.2–12keV with energy resolution of 130eV at 5.9keV, and a field of view of 18 � ×18 �
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x ray Imaging spectrometers xis of astro e2
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2005Co-Authors: Hironori Matsumoto, Kiyoshi Hayashida, Katsuji Koyama, H Tsunemi, Takeshi Go Tsuru, Hiroshi Nakajima, Hiroya Yamaguchi, Emi Miyata, K Torii, M NamikiAbstract:Abstract Astro-E2 is the fifth Japanese X-Ray astronomical satellite and will be launched in 2005. The Astro-E2 X-Ray Imaging Spectrometers (XISs) consist of four sets of X-Ray CCD cameras. Each CCD camera has an Imaging area of 1024 × 1024 pixels and covers a region of 18 ′ × 18 ′ on the sky combined with an X-Ray Telescope. One XIS will utilize back-side illuminated (BI) CCDs, and the other three will be equipped with front-side illuminated (FI) CCDs. The BI CCD has a higher quantum efficiency than the FI CCD below 2 keV, while the FI CCD is more sensitive to X-Rays above 5 keV than the BI CCD. Both types of the CCDs have nearly the same energy resolution (full-width at half-maximum ( FWHM ) = ∼ 130 eV at 6 keV). All four cameras have a charge injection capability and 55 Fe calibration sources, and we can correct the change of the gain and recover the degradation of the energy resolution due to radiation damage caused by cosmic rays. The sensors are cooled to - 90 ∘ C to minimize thermal noise in orbit. The low temperature is also helpful to reduce the influence of the radiation damage.
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high energy performance of x ray Imaging spectrometers on board astro e
Astronomical Telescopes and Instrumentation, 2000Co-Authors: Kensuke Imanishi, Takeshi Go Tsuru, Hisamitsu Awaki, Kenji Hamaguchi, Hiroshi Murakami, Mamiko Nishiuchi, Katsuji KoyamaAbstract:We present the detailed study of the response function of X- ray CCD cameras (XIS; X-Ray Imaging Spectrometer). A pulse height distribution for monochromatic X-Rays show a low- energy tail component and several weak lines in addition to main peak corresponding to incident X-Ray energy. We divided the response function into six components; main peak, sub peak, triangle component, constant component, Si escape, and Si line. Each of them represents different physical processes in the CCD. We did the data fitting, numerical calculations, and Monte Carlo simulations to study energy dependence of the shape and intensity of these components, and made the response function as a function of X-Ray energy.
Jan C. Wessel - One of the best experts on this subject based on the ideXlab platform.
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Photon Counting Energy Dispersive Detector Arrays for X-Ray Imaging
IEEE Transactions on Nuclear Science, 2009Co-Authors: Jan S. Iwanczyk, Oded Meirav, Jerry Arenson, William C. Barber, Nail Malakhov, Eigil Nygård, Neal E. Hartsough, Jan C. WesselAbstract: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/mm2 /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 times 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 57Co source. An output rate of 6 times 106 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-\n our prototype photon-counting and energy-dispersive detector modules, are shown.
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photon counting energy dispersive detector arrays for x ray Imaging
IEEE Nuclear Science Symposium, 2007Co-Authors: Jan S. Iwanczyk, Oded Meirav, Jerry Arenson, William C. Barber, Nail Malakhov, Neal E. Hartsough, Einar Nygard, Jan C. WesselAbstract: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 (CdZnTe) 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 reduced X-Ray dose to the patient. Very high X-Ray flux are utilized in many of these applications. For example, CT scanners can produce ~100 Mphotons/mm2/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 CdZnTe detector array structures which are 3 mm thick with 16 x 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. An output rate of 6 x 106 counts per second per individual pixel has been obtained with ASIC readout electronics. Additionally, the first clinical CT images, taken with several of our prototype photon counting and energy dispersive detector modules, are shown.
Heinz Graafsma - One of the best experts on this subject based on the ideXlab platform.
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x ray Imaging detectors for synchrotron and xfel sources
IUCrJ, 2015Co-Authors: Takaki Hatsui, Heinz GraafsmaAbstract:Current trends for X-Ray Imaging detectors based on hybrid and monolithic detector technologies are reviewed. Hybrid detectors with photon-counting pixels have proven to be very powerful tools at synchrotrons. Recent developments continue to improve their performance, especially for higher spatial resolution at higher count rates with higher frame rates. Recent developments for X-Ray free-electron laser (XFEL) experiments provide high-frame-rate integrating detectors with both high sensitivity and high peak signal. Similar performance improvements are sought in monolithic detectors. The monolithic approach also offers a lower noise floor, which is required for the detection of soft X-Ray photons. The link between technology development and detector performance is described briefly in the context of potential future capabilities for X-Ray Imaging detectors.
Kamel Fezzaa - One of the best experts on this subject based on the ideXlab platform.
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Real time observation of binder jetting printing process using high-speed X-Ray Imaging
Nature Publishing Group, 2019Co-Authors: Niranjan D. Parab, Cang Zhao, John E. Barnes, Ross W. Cunningham, Kamel Fezzaa, Anthony D. Rollett, Tao SunAbstract:Abstract A high-speed synchrotron X-Ray Imaging technique was used to investigate the binder jetting additive manufacturing (AM) process. A commercial binder jetting printer with droplet-on-demand ink-jet print-head was used to print single lines on powder beds. The printing process was recorded in real time using high-speed X-Ray Imaging. The ink-jet droplets showed distinct elongated shape with spherical head, long tail, and three to five trailing satellite droplets. Significant drift was observed between the impact points of main droplet and satellite droplets. The impact of the droplet on the powder bed caused movement and ejection of the powder particles. The depth of disturbance in the powder bed from movement and ejection was defined as interaction depth, which is found to be dependent on the size, shape, and material of the powder particles. For smaller powder particles (diameter less than 10 μm), three consecutive binder droplets were observed to coalesce to form large agglomerates. The observations reported here will facilitate the understanding of underlying physics that govern the binder jetting processes, which will then help in improving the quality of parts manufactured using this AM process
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ultrafast x ray Imaging of laser metal additive manufacturing processes
Journal of Synchrotron Radiation, 2018Co-Authors: Niranjan D. Parab, Cang Zhao, Kamel Fezzaa, Anthony D. Rollett, Ross B Cunningham, Luis I Escano, Wes Everhart, Lianyi Chen, Tao SunAbstract:The high-speed synchrotron X-Ray Imaging technique was synchronized with a custom-built laser-melting setup to capture the dynamics of laser powder-bed fusion processes in situ. Various significant phenomena, including vapor-depression and melt-pool dynamics and powder-spatter ejection, were captured with high spatial and temporal resolution. Imaging frame rates of up to 10 MHz were used to capture the rapid changes in these highly dynamic phenomena. At the same time, relatively slow frame rates were employed to capture large-scale changes during the process. This experimental platform will be vital in the further understanding of laser additive manufacturing processes and will be particularly helpful in guiding efforts to reduce or eliminate microstructural defects in additively manufactured parts.
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high speed synchrotron x ray Imaging studies of the ultrasound shockwave and enhanced flow during metal solidification processes
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2015Co-Authors: Jia Chuan Khong, Kamel Fezzaa, T Connolley, Jiawei MiAbstract:The highly dynamic behavior of ultrasonic bubble implosion in liquid metal, the multiphase liquid metal flow containing bubbles and particles, and the interaction between ultrasonic waves and semisolid phases during solidification of metal were studied in situ using the complementary ultrafast and high-speed synchrotron X-Ray Imaging facilities housed, respectively, at the Advanced Photon Source, Argonne National Laboratory, US, and Diamond Light Source, UK. Real-time ultrafast X-Ray Imaging of 135,780 frames per second revealed that ultrasonic bubble implosion in a liquid Bi-8 wt pctZn alloy can occur in a single wave period (30 kHz), and the effective region affected by the shockwave at implosion was 3.5 times the original bubble diameter. Furthermore, ultrasound bubbles in liquid metal move faster than the primary particles, and the velocity of bubbles is 70 ~ 100 pct higher than that of the primary particles present in the same locations close to the sonotrode. Ultrasound waves can very effectively create a strong swirling flow in a semisolid melt in less than one second. The energetic flow can detach solid particles from the liquid–solid interface and redistribute them back into the bulk liquid very effectively.
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quantitative characterization of inertial confinement fusion capsules using phase contrast enhanced x ray Imaging
Journal of Applied Physics, 2005Co-Authors: Bernard Kozioziemski, J A Koch, Anton Barty, H E Martz, Wahkeat Lee, Kamel FezzaaAbstract:Current designs for inertial confinement fusion capsules for the National Ignition Facility consist of a solid deuterium–tritium (D–T) fuel layer inside of a copper doped beryllium, Be(Cu), shell. Phase contrast enhanced X-Ray Imaging is shown to render the D–T layer visible inside the Be(Cu) shell. Phase contrast Imaging is experimentally demonstrated for several surrogate capsules and validates computational models. Polyimide and low density divinyl benzene foam shells were imaged at the Advanced Photon Source synchrotron. The surrogates demonstrate that phase contrast enhanced Imaging provides a method to characterize surfaces when absorption Imaging cannot be used. Our computational models demonstrate that a rough surface can be accurately characterized using phase contrast enhanced X-Ray images.
Jan S. Iwanczyk - One of the best experts on this subject based on the ideXlab platform.
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Photon Counting Energy Dispersive Detector Arrays for X-Ray Imaging
IEEE Transactions on Nuclear Science, 2009Co-Authors: Jan S. Iwanczyk, Oded Meirav, Jerry Arenson, William C. Barber, Nail Malakhov, Eigil Nygård, Neal E. Hartsough, Jan C. WesselAbstract: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/mm2 /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 times 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 57Co source. An output rate of 6 times 106 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-\n our prototype photon-counting and energy-dispersive detector modules, are shown.
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photon counting energy dispersive detector arrays for x ray Imaging
IEEE Nuclear Science Symposium, 2007Co-Authors: Jan S. Iwanczyk, Oded Meirav, Jerry Arenson, William C. Barber, Nail Malakhov, Neal E. Hartsough, Einar Nygard, Jan C. WesselAbstract: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 (CdZnTe) 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 reduced X-Ray dose to the patient. Very high X-Ray flux are utilized in many of these applications. For example, CT scanners can produce ~100 Mphotons/mm2/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 CdZnTe detector array structures which are 3 mm thick with 16 x 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. An output rate of 6 x 106 counts per second per individual pixel has been obtained with ASIC readout electronics. Additionally, the first clinical CT images, taken with several of our prototype photon counting and energy dispersive detector modules, are shown.
