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Michael Mcguirk - One of the best experts on this subject based on the ideXlab platform.
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the chandra high Energy Transmission grating design fabrication ground calibration and 5 years in flight
Publications of the Astronomical Society of the Pacific, 2005Co-Authors: C R Canizares, John E Davis, D Dewey, Kathryn A Flanagan, Eugene B Galton, David P Huenemoerder, Kazunori Ishibashi, T H Markert, H L Marshall, Michael McguirkAbstract:ABSTRACT Details of the design, fabrication, and ground and flight calibration of the High Energy Transmission Grating (HETG) on the Chandra X‐Ray Observatory are presented after 5 years of flight experience. Specifics include the theory of phased Transmission gratings as applied to the HETG, the Rowland design of the spectrometer, details of the grating fabrication techniques, and the results of ground testing and calibration of the HETG. For nearly 6 years the HETG has operated essentially as designed, although it has presented some subtle flight calibration effects.
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the chandra high Energy Transmission grating design fabrication ground calibration and five years in flight
arXiv: Astrophysics, 2005Co-Authors: C R Canizares, John E Davis, D Dewey, Kathryn A Flanagan, Eugene B Galton, David P Huenemoerder, Kazunori Ishibashi, T H Markert, H L Marshall, Michael McguirkAbstract:Details of the design, fabrication, ground and flight calibration of the High Energy Transmission Grating, HETG, on the Chandra X-ray Observatory are presented after five years of flight experience. Specifics include the theory of phased Transmission gratings as applied to the HETG, the Rowland design of the spectrometer, details of the grating fabrication techniques, and the results of ground testing and calibration of the HETG. For nearly six years the HETG has operated essentially as designed, although it has presented some subtle flight calibration effects.
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high Energy Transmission grating spectrometer for the advanced x ray astrophysics facility axaf
SPIE's 1994 International Symposium on Optics Imaging and Instrumentation, 1994Co-Authors: T H Markert, C R Canizares, D Dewey, Michael Mcguirk, Christopher Pak, Mark L SchattenburgAbstract:The High Energy Transmission Grating Spectrometer (HETGS) is one of the scientific instruments being developed for NASA's Advanced X-ray Astrophysics Facility (AXAF), scheduled for launch in 1998. The HETGS will be capable of measuring spectra with high resolution and sensitivity from a variety of compact and slightly extended cosmic X-ray sources. In this paper we describe the overall design of the HETGS and its expected scientific performance. The HETGS consists of two arrays of gold grating elements (High-Energy gratings [HEGs] and Medium-Energy Gratings [MEGs] which are optimized for the Energy ranges 0.8-10 keV [HEG] and 0.4-5 keV [MEG]). The details of the grating elements and their fabrication methods are described in Schattenburg et al. (this conference). The gratings are mounted on a support plate which can be inserted immediately behind the AXAF telescope assembly. X-rays diffracted by the gratings are dispersed onto the focal plane detector strips which are components of either of the two AXAF imagers (the HRC or ACIS). The two kinds of gratings are oriented at a slight angle with respect to each other so that the dispersed spectra form a shallow 'X' on the readout device. The gratings and detectors are mounted on a Rowland torus to correct for most of the optical aberrations. The grating-detector combination achieves resolving powers (E/(Delta) E) as high as 1000 at some energies, and has significant effective area (10-200 square cm) for all energies 400 eV < E < 10 keV.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
D Dewey - One of the best experts on this subject based on the ideXlab platform.
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the chandra high Energy Transmission grating design fabrication ground calibration and 5 years in flight
Publications of the Astronomical Society of the Pacific, 2005Co-Authors: C R Canizares, John E Davis, D Dewey, Kathryn A Flanagan, Eugene B Galton, David P Huenemoerder, Kazunori Ishibashi, T H Markert, H L Marshall, Michael McguirkAbstract:ABSTRACT Details of the design, fabrication, and ground and flight calibration of the High Energy Transmission Grating (HETG) on the Chandra X‐Ray Observatory are presented after 5 years of flight experience. Specifics include the theory of phased Transmission gratings as applied to the HETG, the Rowland design of the spectrometer, details of the grating fabrication techniques, and the results of ground testing and calibration of the HETG. For nearly 6 years the HETG has operated essentially as designed, although it has presented some subtle flight calibration effects.
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the chandra high Energy Transmission grating design fabrication ground calibration and five years in flight
arXiv: Astrophysics, 2005Co-Authors: C R Canizares, John E Davis, D Dewey, Kathryn A Flanagan, Eugene B Galton, David P Huenemoerder, Kazunori Ishibashi, T H Markert, H L Marshall, Michael McguirkAbstract:Details of the design, fabrication, ground and flight calibration of the High Energy Transmission Grating, HETG, on the Chandra X-ray Observatory are presented after five years of flight experience. Specifics include the theory of phased Transmission gratings as applied to the HETG, the Rowland design of the spectrometer, details of the grating fabrication techniques, and the results of ground testing and calibration of the HETG. For nearly six years the HETG has operated essentially as designed, although it has presented some subtle flight calibration effects.
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high resolution x ray spectra of capella initial results from the chandra high Energy Transmission grating spectrometer
The Astrophysical Journal, 2000Co-Authors: Claude R Canizares, D Dewey, Kathryn A Flanagan, David P Huenemoerder, T H Markert, H L Marshall, David S Davis, J C Houck, Mark L Schattenburg, Norbert S SchulzAbstract:High-resolution spectra of the active binary Capella (G8 III + G1 III) covering the Energy range of 0.4-8.0 keV (1.5-30 A) show a large number of emission lines, demonstrating the performance of the High-Energy Transmission Grating Spectrometer. A preliminary application of plasma diagnostics provides information on coronal temperatures and densities. Lines arising from different elements in a range of ionization states indicate that Capella has plasma with a broad range of temperatures, from log T = 6.3 to 7.2, generally consistent with recent results from observations with the Extreme-Ultraviolet Explorer and the Advanced Satellite for Cosmology and Astrophysics. The electron density is determined from He-like O VII lines, giving the value of Ne ~ 1010 cm-3 at Te ~ 2 × 106 K; He-like lines formed at higher temperatures give only upper limits to the electron density. The density and emission measure from O VII lines together indicate that the coronal loops are significantly smaller than the stellar radius.
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x ray calibration of the axaf low Energy Transmission grating spectrometer effective area
Grazing Incidence and Multilayer X-Ray Optical Systems, 1997Co-Authors: P Predehl, D Dewey, Kathryn A Flanagan, A C Brinkman, Heinrich W Braeuninger, Jeremy J Drake, Theo Gunsing, Gisela Hartner, Jiahong Zhang Juda, M JudaAbstract:The low Energy Transmission grating spectrometer (LETGS) on board the Advanced X-ray Astrophysics Facility provides high resolution dispersive spectroscopy between 70 eV and more than 7 keV. The LETG contains 180 grating modules, each equipped with 3 grating facets. The freestanding gold gratings have 1008 lines per mm. Early 1997, the AXAF telescope underwent extended calibrations in the long beam X-Ray Calibration Facility at the NASA/Marshall Space Flight Center. As part of the telescope, also the performance of the LETGS with respect of spectral resolving power and effective area was measured. At more than 50 individual energies we have measured the grating efficiency or the effective area of the spectrometer, respectively. All these energies were chosen in order to cover the numerous spectral features due to absorption edges of filters, detector coatings, mirror reflectivities, and grating efficiency variations. Although preliminary, the performance of the gratings is close to the predictions made on the basis of subassembly measurements of individual grating elements. In particular, the first order efficiency is about 15% (both sides including vignetting effects) outside the Energy regime of partial transparency of the grating wires; inside the efficiency gains from constructive interference effects. Both first diffraction orders are symmetric within less than 1%. The second order is suppressed by a factor of about 200 relative to the first order.
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high Energy Transmission grating spectrometer for the advanced x ray astrophysics facility axaf
SPIE's 1994 International Symposium on Optics Imaging and Instrumentation, 1994Co-Authors: T H Markert, C R Canizares, D Dewey, Michael Mcguirk, Christopher Pak, Mark L SchattenburgAbstract:The High Energy Transmission Grating Spectrometer (HETGS) is one of the scientific instruments being developed for NASA's Advanced X-ray Astrophysics Facility (AXAF), scheduled for launch in 1998. The HETGS will be capable of measuring spectra with high resolution and sensitivity from a variety of compact and slightly extended cosmic X-ray sources. In this paper we describe the overall design of the HETGS and its expected scientific performance. The HETGS consists of two arrays of gold grating elements (High-Energy gratings [HEGs] and Medium-Energy Gratings [MEGs] which are optimized for the Energy ranges 0.8-10 keV [HEG] and 0.4-5 keV [MEG]). The details of the grating elements and their fabrication methods are described in Schattenburg et al. (this conference). The gratings are mounted on a support plate which can be inserted immediately behind the AXAF telescope assembly. X-rays diffracted by the gratings are dispersed onto the focal plane detector strips which are components of either of the two AXAF imagers (the HRC or ACIS). The two kinds of gratings are oriented at a slight angle with respect to each other so that the dispersed spectra form a shallow 'X' on the readout device. The gratings and detectors are mounted on a Rowland torus to correct for most of the optical aberrations. The grating-detector combination achieves resolving powers (E/(Delta) E) as high as 1000 at some energies, and has significant effective area (10-200 square cm) for all energies 400 eV < E < 10 keV.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Kathryn A Flanagan - One of the best experts on this subject based on the ideXlab platform.
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the chandra high Energy Transmission grating design fabrication ground calibration and 5 years in flight
Publications of the Astronomical Society of the Pacific, 2005Co-Authors: C R Canizares, John E Davis, D Dewey, Kathryn A Flanagan, Eugene B Galton, David P Huenemoerder, Kazunori Ishibashi, T H Markert, H L Marshall, Michael McguirkAbstract:ABSTRACT Details of the design, fabrication, and ground and flight calibration of the High Energy Transmission Grating (HETG) on the Chandra X‐Ray Observatory are presented after 5 years of flight experience. Specifics include the theory of phased Transmission gratings as applied to the HETG, the Rowland design of the spectrometer, details of the grating fabrication techniques, and the results of ground testing and calibration of the HETG. For nearly 6 years the HETG has operated essentially as designed, although it has presented some subtle flight calibration effects.
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the chandra high Energy Transmission grating design fabrication ground calibration and five years in flight
arXiv: Astrophysics, 2005Co-Authors: C R Canizares, John E Davis, D Dewey, Kathryn A Flanagan, Eugene B Galton, David P Huenemoerder, Kazunori Ishibashi, T H Markert, H L Marshall, Michael McguirkAbstract:Details of the design, fabrication, ground and flight calibration of the High Energy Transmission Grating, HETG, on the Chandra X-ray Observatory are presented after five years of flight experience. Specifics include the theory of phased Transmission gratings as applied to the HETG, the Rowland design of the spectrometer, details of the grating fabrication techniques, and the results of ground testing and calibration of the HETG. For nearly six years the HETG has operated essentially as designed, although it has presented some subtle flight calibration effects.
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high resolution x ray spectra of capella initial results from the chandra high Energy Transmission grating spectrometer
The Astrophysical Journal, 2000Co-Authors: Claude R Canizares, D Dewey, Kathryn A Flanagan, David P Huenemoerder, T H Markert, H L Marshall, David S Davis, J C Houck, Mark L Schattenburg, Norbert S SchulzAbstract:High-resolution spectra of the active binary Capella (G8 III + G1 III) covering the Energy range of 0.4-8.0 keV (1.5-30 A) show a large number of emission lines, demonstrating the performance of the High-Energy Transmission Grating Spectrometer. A preliminary application of plasma diagnostics provides information on coronal temperatures and densities. Lines arising from different elements in a range of ionization states indicate that Capella has plasma with a broad range of temperatures, from log T = 6.3 to 7.2, generally consistent with recent results from observations with the Extreme-Ultraviolet Explorer and the Advanced Satellite for Cosmology and Astrophysics. The electron density is determined from He-like O VII lines, giving the value of Ne ~ 1010 cm-3 at Te ~ 2 × 106 K; He-like lines formed at higher temperatures give only upper limits to the electron density. The density and emission measure from O VII lines together indicate that the coronal loops are significantly smaller than the stellar radius.
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x ray calibration of the axaf low Energy Transmission grating spectrometer effective area
Grazing Incidence and Multilayer X-Ray Optical Systems, 1997Co-Authors: P Predehl, D Dewey, Kathryn A Flanagan, A C Brinkman, Heinrich W Braeuninger, Jeremy J Drake, Theo Gunsing, Gisela Hartner, Jiahong Zhang Juda, M JudaAbstract:The low Energy Transmission grating spectrometer (LETGS) on board the Advanced X-ray Astrophysics Facility provides high resolution dispersive spectroscopy between 70 eV and more than 7 keV. The LETG contains 180 grating modules, each equipped with 3 grating facets. The freestanding gold gratings have 1008 lines per mm. Early 1997, the AXAF telescope underwent extended calibrations in the long beam X-Ray Calibration Facility at the NASA/Marshall Space Flight Center. As part of the telescope, also the performance of the LETGS with respect of spectral resolving power and effective area was measured. At more than 50 individual energies we have measured the grating efficiency or the effective area of the spectrometer, respectively. All these energies were chosen in order to cover the numerous spectral features due to absorption edges of filters, detector coatings, mirror reflectivities, and grating efficiency variations. Although preliminary, the performance of the gratings is close to the predictions made on the basis of subassembly measurements of individual grating elements. In particular, the first order efficiency is about 15% (both sides including vignetting effects) outside the Energy regime of partial transparency of the grating wires; inside the efficiency gains from constructive interference effects. Both first diffraction orders are symmetric within less than 1%. The second order is suppressed by a factor of about 200 relative to the first order.
T H Markert - One of the best experts on this subject based on the ideXlab platform.
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the chandra high Energy Transmission grating design fabrication ground calibration and 5 years in flight
Publications of the Astronomical Society of the Pacific, 2005Co-Authors: C R Canizares, John E Davis, D Dewey, Kathryn A Flanagan, Eugene B Galton, David P Huenemoerder, Kazunori Ishibashi, T H Markert, H L Marshall, Michael McguirkAbstract:ABSTRACT Details of the design, fabrication, and ground and flight calibration of the High Energy Transmission Grating (HETG) on the Chandra X‐Ray Observatory are presented after 5 years of flight experience. Specifics include the theory of phased Transmission gratings as applied to the HETG, the Rowland design of the spectrometer, details of the grating fabrication techniques, and the results of ground testing and calibration of the HETG. For nearly 6 years the HETG has operated essentially as designed, although it has presented some subtle flight calibration effects.
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the chandra high Energy Transmission grating design fabrication ground calibration and five years in flight
arXiv: Astrophysics, 2005Co-Authors: C R Canizares, John E Davis, D Dewey, Kathryn A Flanagan, Eugene B Galton, David P Huenemoerder, Kazunori Ishibashi, T H Markert, H L Marshall, Michael McguirkAbstract:Details of the design, fabrication, ground and flight calibration of the High Energy Transmission Grating, HETG, on the Chandra X-ray Observatory are presented after five years of flight experience. Specifics include the theory of phased Transmission gratings as applied to the HETG, the Rowland design of the spectrometer, details of the grating fabrication techniques, and the results of ground testing and calibration of the HETG. For nearly six years the HETG has operated essentially as designed, although it has presented some subtle flight calibration effects.
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high resolution x ray spectra of capella initial results from the chandra high Energy Transmission grating spectrometer
The Astrophysical Journal, 2000Co-Authors: Claude R Canizares, D Dewey, Kathryn A Flanagan, David P Huenemoerder, T H Markert, H L Marshall, David S Davis, J C Houck, Mark L Schattenburg, Norbert S SchulzAbstract:High-resolution spectra of the active binary Capella (G8 III + G1 III) covering the Energy range of 0.4-8.0 keV (1.5-30 A) show a large number of emission lines, demonstrating the performance of the High-Energy Transmission Grating Spectrometer. A preliminary application of plasma diagnostics provides information on coronal temperatures and densities. Lines arising from different elements in a range of ionization states indicate that Capella has plasma with a broad range of temperatures, from log T = 6.3 to 7.2, generally consistent with recent results from observations with the Extreme-Ultraviolet Explorer and the Advanced Satellite for Cosmology and Astrophysics. The electron density is determined from He-like O VII lines, giving the value of Ne ~ 1010 cm-3 at Te ~ 2 × 106 K; He-like lines formed at higher temperatures give only upper limits to the electron density. The density and emission measure from O VII lines together indicate that the coronal loops are significantly smaller than the stellar radius.
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high Energy Transmission grating spectrometer for the advanced x ray astrophysics facility axaf
SPIE's 1994 International Symposium on Optics Imaging and Instrumentation, 1994Co-Authors: T H Markert, C R Canizares, D Dewey, Michael Mcguirk, Christopher Pak, Mark L SchattenburgAbstract:The High Energy Transmission Grating Spectrometer (HETGS) is one of the scientific instruments being developed for NASA's Advanced X-ray Astrophysics Facility (AXAF), scheduled for launch in 1998. The HETGS will be capable of measuring spectra with high resolution and sensitivity from a variety of compact and slightly extended cosmic X-ray sources. In this paper we describe the overall design of the HETGS and its expected scientific performance. The HETGS consists of two arrays of gold grating elements (High-Energy gratings [HEGs] and Medium-Energy Gratings [MEGs] which are optimized for the Energy ranges 0.8-10 keV [HEG] and 0.4-5 keV [MEG]). The details of the grating elements and their fabrication methods are described in Schattenburg et al. (this conference). The gratings are mounted on a support plate which can be inserted immediately behind the AXAF telescope assembly. X-rays diffracted by the gratings are dispersed onto the focal plane detector strips which are components of either of the two AXAF imagers (the HRC or ACIS). The two kinds of gratings are oriented at a slight angle with respect to each other so that the dispersed spectra form a shallow 'X' on the readout device. The gratings and detectors are mounted on a Rowland torus to correct for most of the optical aberrations. The grating-detector combination achieves resolving powers (E/(Delta) E) as high as 1000 at some energies, and has significant effective area (10-200 square cm) for all energies 400 eV < E < 10 keV.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
David P Huenemoerder - One of the best experts on this subject based on the ideXlab platform.
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the chandra high Energy Transmission grating design fabrication ground calibration and 5 years in flight
Publications of the Astronomical Society of the Pacific, 2005Co-Authors: C R Canizares, John E Davis, D Dewey, Kathryn A Flanagan, Eugene B Galton, David P Huenemoerder, Kazunori Ishibashi, T H Markert, H L Marshall, Michael McguirkAbstract:ABSTRACT Details of the design, fabrication, and ground and flight calibration of the High Energy Transmission Grating (HETG) on the Chandra X‐Ray Observatory are presented after 5 years of flight experience. Specifics include the theory of phased Transmission gratings as applied to the HETG, the Rowland design of the spectrometer, details of the grating fabrication techniques, and the results of ground testing and calibration of the HETG. For nearly 6 years the HETG has operated essentially as designed, although it has presented some subtle flight calibration effects.
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the chandra high Energy Transmission grating design fabrication ground calibration and five years in flight
arXiv: Astrophysics, 2005Co-Authors: C R Canizares, John E Davis, D Dewey, Kathryn A Flanagan, Eugene B Galton, David P Huenemoerder, Kazunori Ishibashi, T H Markert, H L Marshall, Michael McguirkAbstract:Details of the design, fabrication, ground and flight calibration of the High Energy Transmission Grating, HETG, on the Chandra X-ray Observatory are presented after five years of flight experience. Specifics include the theory of phased Transmission gratings as applied to the HETG, the Rowland design of the spectrometer, details of the grating fabrication techniques, and the results of ground testing and calibration of the HETG. For nearly six years the HETG has operated essentially as designed, although it has presented some subtle flight calibration effects.
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high resolution x ray spectra of capella initial results from the chandra high Energy Transmission grating spectrometer
The Astrophysical Journal, 2000Co-Authors: Claude R Canizares, D Dewey, Kathryn A Flanagan, David P Huenemoerder, T H Markert, H L Marshall, David S Davis, J C Houck, Mark L Schattenburg, Norbert S SchulzAbstract:High-resolution spectra of the active binary Capella (G8 III + G1 III) covering the Energy range of 0.4-8.0 keV (1.5-30 A) show a large number of emission lines, demonstrating the performance of the High-Energy Transmission Grating Spectrometer. A preliminary application of plasma diagnostics provides information on coronal temperatures and densities. Lines arising from different elements in a range of ionization states indicate that Capella has plasma with a broad range of temperatures, from log T = 6.3 to 7.2, generally consistent with recent results from observations with the Extreme-Ultraviolet Explorer and the Advanced Satellite for Cosmology and Astrophysics. The electron density is determined from He-like O VII lines, giving the value of Ne ~ 1010 cm-3 at Te ~ 2 × 106 K; He-like lines formed at higher temperatures give only upper limits to the electron density. The density and emission measure from O VII lines together indicate that the coronal loops are significantly smaller than the stellar radius.