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Satoru Katsuda - One of the best experts on this subject based on the ideXlab platform.
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Performance of the Charge Injection Capability of Suzaku XIS
Publications of the Astronomical Society of Japan, 2008Co-Authors: Hiroshi Nakajima, Hiroya Yamaguchi, Hironori Matsumoto, Takeshi Go Tsuru, Katsuji Koyama, Hiroshi Tsunemi, Kiyoshi Hayashida, Ken'ichi Torii, Masaaki Namiki, Satoru KatsudaAbstract:A Charge Injection technique is applied to the X-ray CCD camera, XIS (X-ray Imaging Spectrometer) onboard Suzaku. The Charge transfer inefficiency (CTI) in each CCD column (vertical transfer channel) is measured by the Injection of Charge packets into a transfer channel and subsequent readout. This paper reports the performances of the Charge Injection capability based on the ground experiments using a radiation damaged device, and in-orbit measurements of the XIS. The ground experiments show that Charges are stably injected with the dispersion of 91eV in FWHM in a specific column for the Charges equivalent to the X-ray energy of 5.1keV. This dispersion width is significantly smaller than that of the X-ray events of 113eV (FWHM) at approximately the same energy. The amount of Charge loss during transfer in a specific column, which is measured with the Charge Injection capability, is consistent with that measured with the calibration source. These results indicate that the Charge Injection technique can accurately measure column-dependent Charge losses rather than the calibration sources. The column-to-column CTI correction to the calibration source spectra significantly reduces the line widths compared to those with a column-averaged CTI correction (from 193eV to 173eV in FWHM on an average at the time of one year after the launch). In addition, this method significantly reduces the low energy tail in the line profile of the calibration source spectrum.
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performance of the Charge Injection capability of suzaku xis
Publications of the Astronomical Society of Japan, 2008Co-Authors: Hiroshi Nakajima, Hiroya Yamaguchi, Hironori Matsumoto, Takeshi Go Tsuru, Katsuji Koyama, Hiroshi Tsunemi, Kiyoshi Hayashida, Masaaki Namiki, K Torii, Satoru KatsudaAbstract:A Charge-Injection technique is applied to the X-ray CCD camera, XIS (X-ray Imaging Spectrometer) aboard Suzaku. The Charge transfer inefficiency (CTI) in each CCD column (vertical transfer channel) is measured by the Injection of Charge packets into a transfer channel and subsequent readout. This paper reports on the performances of the Charge-Injection capability based on the ground experiments using a radiation-damaged device, and in-orbit measurements of the XIS. The ground experiments show that Charges are stably injected with a dispersion of 91 eV in FWHM in a specific column for the Charges equivalent to an X-ray energy of 5.1 keV. This dispersion width is significantly smaller than that of the X-ray events of 113 eV (FWHM) at approximately the same energy. The amount of Charge loss during transfer in a specific column, which is measured with the Charge-Injection capability, is consistent with that measured with the calibration source. These results indicate that the Charge-Injection technique can accurately measure column-dependent Charge losses, rather than the calibration sources. The column-to-column CTI correction to the calibration source spectra significantly reduces the line widths compared to those with a columnaveraged CTI correction (from 193 eV to 173 eV in FWHM on an average at the time of one year after the launch). In addition, this method significantly reduces the low-energy tail in the line profile of the calibration source spectrum.
Yewen Zhang - One of the best experts on this subject based on the ideXlab platform.
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Charge Injection behaviors of surface oxyfluorinated linear low density polyethylene
2010 10th IEEE International Conference on Solid Dielectrics, 2010Co-Authors: Yue Jiang, Chenxia Liu, Feihu Zheng, Yewen ZhangAbstract:Linear low density polyethylene discs were surface oxyfluorinated for different time to investigate the influences on Charge Injection from carbon black loaded poly(ethylene-co-vinyl acetate) (EVA) electrode and Charge accumulation in bulk under direct current high voltage. The oxyfluorination leads to the substantial variation in chemical composition, forming various polar groups in the surface layer. The Charge Injection and accumulation are revealed by space Charge measurements. Suppression of Charge Injection is enhanced by extending oxyfluorination time. Diffusion of the volatile by-products within the EVA electrode and its influences on Charge accumulation and Charge traps of surface layer are evidenced. The suppression mechanisms of the Charge Injection are largely attributed to the remarkable increase in permittivity, together with the change in Charge traps of the oxyfluorinated surface layer.
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suppression effect of surface fluorination on Charge Injection into linear low density polyethylene
Journal of Applied Physics, 2009Co-Authors: Q. Yang, Yue Jiang, Feihu Zheng, Chen Xie, Yewen ZhangAbstract:To suppress Charge Injection from electrodes, direct fluorination using fluorine gas was used for linear low density polyethylene (LLDPE) since it is one of the most effective methods of the polymer surface modification. Surface fluorination of the LLDPE plates was obtained as indicated by attenuated total reflection infrared spectroscopy. Remarkable suppression of Charge Injection by the surface fluorination was observed by space Charge distribution measurements using the pressure wave propagation method. Comparing with the remarkable bipolar Charge distribution in bulk of the original LLDPE, there is less space Charge in bulk and it mostly exists in the fluorinated surface layers. The possible mechanisms of the Charge Injection suppression are discussed, one of which, the effect of fluorination on the Charge traps in surface layer was investigated by the thermally stimulated disCharge technique. The results indicate that fluorination has Charge traps in the surface layer remarkably deepened and Charges ...
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Suppression of Charge Injection to linear low density polyethylene by surface fluorination modification
2008 International Symposium on Electrical Insulating Materials (ISEIM 2008), 2008Co-Authors: Q. Yang, Yue Jiang, Feihu Zheng, Chen Xie, Yewen ZhangAbstract:To suppress Charge Injection at electrodes, direct fluorination using fluorine gas was used in linear low density polyethylene. High fluorination degree was obtained as indicated by attenuated total reflection infrared spectroscopy. Remarkable suppression of Charge Injection due to the surface fluorination was found by the space Charge distribution measurements using the laser-induced pressure pulse method. The possible suppression mechanisms of Charge Injection were discussed, one of which, the effect of fluorination on the Charge traps in surface layer was deeply investigated by the thermally stimulated disCharge technique. The results indicate that fluorination caused the Charge traps in surface layer remarkably deepened and the Charge captured in the deep traps blocked or shielded the further Charge Injection.
L. Bullara - One of the best experts on this subject based on the ideXlab platform.
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"Safe" Charge-Injection waveforms for iridium oxide (AIROF) microelectrodes
The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2004Co-Authors: P.r. Troyk, S.f. Cogan, J. Ehrlich, D.b. Mccreery, L. Bullara, D.e. Detlefsen, M. Bak, E. SchmidtAbstract:Use of anodic bias improves the Charge-Injection limits of activated iridium oxide (AIROF) microelectrodes. Asymmetric waveforms, in which the Charge balancing anodic phase is delivered at a lower current density and longer pulse width, has been found to allow for higher values of anodic bias voltages, thus maximizing the AIROF Charge-Injection capacity. Limiting the voltage excursion of the AIROF below the value at which electrolysis of water occurs is essential to maintaining the long-term viability of implanted electrodes. However, maintaining the electrodes at an anodic bias state while keeping the electrode voltage within these electrochemically "safe" limits complicates the topology of the electronic driver circuitry. We present two possible driver topologies that use compliance-voltage limitation in combination with cathodic current modification.
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Charge-Injection waveforms for iridium oxide (AIROF) microelectrodes
Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (IEEE Cat. No.03CH37439), 2003Co-Authors: S.f. Cogan, P.r. Troyk, J. Ehrlich, T.d. Plante, D.b. Mccreery, L. BullaraAbstract:The Charge-Injection limits of activated iridium oxide (AIROF) microelectrodes subjected to Charge-balanced biphasic current pulsing are investigated as a function of anodic bias and asymmetry in the cathodic and anodic pulse widths. The use of asymmetric waveforms, in which the Charge balancing anodic phase is delivered at a lower current density and longer pulse width, permits the use of anodic biasing to maximize Charge-Injection capacity. The need for more sophisticated driving waveforms and how these could be implemented in modern ASIC design to achieve optimal Charge-Injection is discussed.
Hiroshi Nakajima - One of the best experts on this subject based on the ideXlab platform.
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Performance of the Charge Injection Capability of Suzaku XIS
Publications of the Astronomical Society of Japan, 2008Co-Authors: Hiroshi Nakajima, Hiroya Yamaguchi, Hironori Matsumoto, Takeshi Go Tsuru, Katsuji Koyama, Hiroshi Tsunemi, Kiyoshi Hayashida, Ken'ichi Torii, Masaaki Namiki, Satoru KatsudaAbstract:A Charge Injection technique is applied to the X-ray CCD camera, XIS (X-ray Imaging Spectrometer) onboard Suzaku. The Charge transfer inefficiency (CTI) in each CCD column (vertical transfer channel) is measured by the Injection of Charge packets into a transfer channel and subsequent readout. This paper reports the performances of the Charge Injection capability based on the ground experiments using a radiation damaged device, and in-orbit measurements of the XIS. The ground experiments show that Charges are stably injected with the dispersion of 91eV in FWHM in a specific column for the Charges equivalent to the X-ray energy of 5.1keV. This dispersion width is significantly smaller than that of the X-ray events of 113eV (FWHM) at approximately the same energy. The amount of Charge loss during transfer in a specific column, which is measured with the Charge Injection capability, is consistent with that measured with the calibration source. These results indicate that the Charge Injection technique can accurately measure column-dependent Charge losses rather than the calibration sources. The column-to-column CTI correction to the calibration source spectra significantly reduces the line widths compared to those with a column-averaged CTI correction (from 193eV to 173eV in FWHM on an average at the time of one year after the launch). In addition, this method significantly reduces the low energy tail in the line profile of the calibration source spectrum.
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performance of the Charge Injection capability of suzaku xis
Publications of the Astronomical Society of Japan, 2008Co-Authors: Hiroshi Nakajima, Hiroya Yamaguchi, Hironori Matsumoto, Takeshi Go Tsuru, Katsuji Koyama, Hiroshi Tsunemi, Kiyoshi Hayashida, Masaaki Namiki, K Torii, Satoru KatsudaAbstract:A Charge-Injection technique is applied to the X-ray CCD camera, XIS (X-ray Imaging Spectrometer) aboard Suzaku. The Charge transfer inefficiency (CTI) in each CCD column (vertical transfer channel) is measured by the Injection of Charge packets into a transfer channel and subsequent readout. This paper reports on the performances of the Charge-Injection capability based on the ground experiments using a radiation-damaged device, and in-orbit measurements of the XIS. The ground experiments show that Charges are stably injected with a dispersion of 91 eV in FWHM in a specific column for the Charges equivalent to an X-ray energy of 5.1 keV. This dispersion width is significantly smaller than that of the X-ray events of 113 eV (FWHM) at approximately the same energy. The amount of Charge loss during transfer in a specific column, which is measured with the Charge-Injection capability, is consistent with that measured with the calibration source. These results indicate that the Charge-Injection technique can accurately measure column-dependent Charge losses, rather than the calibration sources. The column-to-column CTI correction to the calibration source spectra significantly reduces the line widths compared to those with a columnaveraged CTI correction (from 193 eV to 173 eV in FWHM on an average at the time of one year after the launch). In addition, this method significantly reduces the low-energy tail in the line profile of the calibration source spectrum.
S.f. Cogan - One of the best experts on this subject based on the ideXlab platform.
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"Safe" Charge-Injection waveforms for iridium oxide (AIROF) microelectrodes
The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2004Co-Authors: P.r. Troyk, S.f. Cogan, J. Ehrlich, D.b. Mccreery, L. Bullara, D.e. Detlefsen, M. Bak, E. SchmidtAbstract:Use of anodic bias improves the Charge-Injection limits of activated iridium oxide (AIROF) microelectrodes. Asymmetric waveforms, in which the Charge balancing anodic phase is delivered at a lower current density and longer pulse width, has been found to allow for higher values of anodic bias voltages, thus maximizing the AIROF Charge-Injection capacity. Limiting the voltage excursion of the AIROF below the value at which electrolysis of water occurs is essential to maintaining the long-term viability of implanted electrodes. However, maintaining the electrodes at an anodic bias state while keeping the electrode voltage within these electrochemically "safe" limits complicates the topology of the electronic driver circuitry. We present two possible driver topologies that use compliance-voltage limitation in combination with cathodic current modification.
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Charge-Injection waveforms for iridium oxide (AIROF) microelectrodes
Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (IEEE Cat. No.03CH37439), 2003Co-Authors: S.f. Cogan, P.r. Troyk, J. Ehrlich, T.d. Plante, D.b. Mccreery, L. BullaraAbstract:The Charge-Injection limits of activated iridium oxide (AIROF) microelectrodes subjected to Charge-balanced biphasic current pulsing are investigated as a function of anodic bias and asymmetry in the cathodic and anodic pulse widths. The use of asymmetric waveforms, in which the Charge balancing anodic phase is delivered at a lower current density and longer pulse width, permits the use of anodic biasing to maximize Charge-Injection capacity. The need for more sophisticated driving waveforms and how these could be implemented in modern ASIC design to achieve optimal Charge-Injection is discussed.
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Stability of electro-active materials and coatings for Charge-Injection electrodes
Proceedings of the Second Joint 24th Annual Conference and the Annual Fall Meeting of the Biomedical Engineering Society] [Engineering in Medicine and, 2002Co-Authors: S.f. CoganAbstract:The stability of materials and coatings for Charge Injection in electrical stimulation with chronically implanted electrodes is reviewed. The focus of the review is iridium oxide, whose performance and Charge-Injection mechanisms are contrasted with other high-Charge capacity materials such as high-surface-area titanium nitride and noble metal coatings, as well as traditional noble metals. The appropriateness of iridium oxide and these materials for applications in functional electrical stimulation is discussed with an emphasis on the stability of their electrochemical function in chronic implants. Gaps in our knowledge of the in vivo electrochemistry and chronic stability of iridium oxide are identified. The structure and electrochemical properties of iridium oxide that permit high Charge Injection capacities are described and thoughts on how these generally desirable features may also compromise the chronic in vivo stability of iridium oxide electrodes are presented.