Design work carried out as part of the pre-phase A studies in support of an orbiting COLUMBUS spe... more Design work carried out as part of the pre-phase A studies in support of an orbiting COLUMBUS spectroscopy observatory is summarized. Also included are new findings resulting from a reanalysis initiated in response to the following guidelines: (1) The strawman satellite design, which assumed a telescope 6 meters in length followed by a 3-meter spectrograph, resulted in an observatory which
High resolution M/sub 4,5/ (3d ..-->.. 4p) x-ray emission spectra from a krypton plasma were m... more High resolution M/sub 4,5/ (3d ..-->.. 4p) x-ray emission spectra from a krypton plasma were measured using a recently developed grazing-incidence reflection-grating monochromator/spectrometer with very high flux rates at extreme ultraviolet and soft x-ray wave lengths. The nominal resolving power of the instrument, E/..delta..E, is about 300 in this energy range (approx.80 eV). Three dipole-allowed 3d ..-->.. 4p emission lines were observed at 80.98 eV, 80.35 eV and 79.73 eV. A broad peak at about 82.3 eV is tentatively assigned to transitions resulting from Kr/sup 2 +/, and effects of excitation energy on M/sub 4,5/ x-ray emission were observed. 9 refs., 3 figs., 1 tab.
Grazing incidence reflection grating design options for faint X-ray source spaceborne observation... more Grazing incidence reflection grating design options for faint X-ray source spaceborne observation are considered. Geometries based on objective gratings and convergent beam varied line-space gratings are discussed. In-plane (classical) and off-plane (conical) grating mountings are compared.
Spectroscopic analysis is a powerful technique for the diagnosis of temperatures and compositions... more Spectroscopic analysis is a powerful technique for the diagnosis of temperatures and compositions of astrophysical plasmas. The EUV (100–1000Å) and soft x-ray (10–100Å) bands contain hundreds of potentially useful diagnostic lines. Unfortunately, traditional types of grating spectrometer become inefficient or unwieldy when adapted to stellar spectroscopy onboard a spacecraft. At grazing incidence, the required length of a high-resolution plane-grating spectrometer can easily exceed the length of the telescope feeding it. For these reasons, we have systematically explored ways to introduce a reflection grating into the converging beam formed by a given objective optical system ahead of its first focus. A spectrometer of this type results in an optical train no longer than the telescope’s existing prime-focus beam.
A new geometric scheme translates a diffraction grating along the straight central groove of an e... more A new geometric scheme translates a diffraction grating along the straight central groove of an exponentially curved pattern. Lit by a stationary incident beam, the two-dimensional pattern scales isotropically, scanning wavelength without change to any angles, macroscopic distances, curvatures or aberrations. This is exemplified by a new class of self-focused grating monochromator, analyzed by rigorous light-path expansion and numerical raytracing. All spectral aberrations in pure meridional powers (including defocus, coma and spherical aberration) cancel for any choice of angular deviation, magnification and translation range. The residual mixed powers yield Δλ/λ = 10<sup>-3</sup> ~ 10<sup>-5</sup> in the soft x-ray for plane and concave gratings at grazing incidence. Over the visible spectrum, Δλ/λ ~ 10<sup>-4</sup>is shown for plane gratings mounted at Littrow and at normal incidence in reflection or transmission.
High resolution M/sub 4,5/ (3d ..-->.. 4p) x-ray emission spectra from a krypton plasma were m... more High resolution M/sub 4,5/ (3d ..-->.. 4p) x-ray emission spectra from a krypton plasma were measured using a recently developed grazing-incidence reflection-grating monochromator/spectrometer with very high flux rates at extreme ultraviolet and soft x-ray wave lengths. The nominal resolving power of the instrument, E/..delta..E, is about 300 in this energy range (approx.80 eV). Three dipole-allowed 3d ..-->.. 4p emission lines were observed at 80.98 eV, 80.35 eV and 79.73 eV. A broad peak at about 82.3 eV is tentatively assigned to transitions resulting from Kr/sup 2 +/, and effects of excitation energy on M/sub 4,5/ x-ray emission were observed. 9 refs., 3 figs., 1 tab.
We have mapped CO emission over a 5° x 5° area in the Cains Major OB1/R1 region. Most of the em... more We have mapped CO emission over a 5° x 5° area in the Cains Major OB1/R1 region. Most of the emission is confied to an elliptical region of approximately 90 x 60 pc. Several CO emission peaks appear, many associated with reflection nebulae. While most of the emission falls in the LSR velocity range 10--20 km sâ»Â¹, we find some material over the full velocity covered (-30 to +45 km sâ»Â¹). There is no simple pattern that would indicate a single expanding shell, but the observations are consistent with the idea that some energetic process, which took place in an initially inhomogeneous cloudy medium, was responsible for the observed morphology of the region. Simple arguments suggest that a supernova explosion is the most likely candidate for this energetic process. The relationship between the process that shaped the clouds and star formation in the region is discussed.
Design work carried out as part of the pre-phase A studies in support of an orbiting COLUMBUS spe... more Design work carried out as part of the pre-phase A studies in support of an orbiting COLUMBUS spectroscopy observatory is summarized. Also included are new findings resulting from a reanalysis initiated in response to the following guidelines: (1) The strawman satellite design, which assumed a telescope 6 meters in length followed by a 3-meter spectrograph, resulted in an observatory which
High resolution M/sub 4,5/ (3d ..-->.. 4p) x-ray emission spectra from a krypton plasma were m... more High resolution M/sub 4,5/ (3d ..-->.. 4p) x-ray emission spectra from a krypton plasma were measured using a recently developed grazing-incidence reflection-grating monochromator/spectrometer with very high flux rates at extreme ultraviolet and soft x-ray wave lengths. The nominal resolving power of the instrument, E/..delta..E, is about 300 in this energy range (approx.80 eV). Three dipole-allowed 3d ..-->.. 4p emission lines were observed at 80.98 eV, 80.35 eV and 79.73 eV. A broad peak at about 82.3 eV is tentatively assigned to transitions resulting from Kr/sup 2 +/, and effects of excitation energy on M/sub 4,5/ x-ray emission were observed. 9 refs., 3 figs., 1 tab.
Grazing incidence reflection grating design options for faint X-ray source spaceborne observation... more Grazing incidence reflection grating design options for faint X-ray source spaceborne observation are considered. Geometries based on objective gratings and convergent beam varied line-space gratings are discussed. In-plane (classical) and off-plane (conical) grating mountings are compared.
Spectroscopic analysis is a powerful technique for the diagnosis of temperatures and compositions... more Spectroscopic analysis is a powerful technique for the diagnosis of temperatures and compositions of astrophysical plasmas. The EUV (100–1000Å) and soft x-ray (10–100Å) bands contain hundreds of potentially useful diagnostic lines. Unfortunately, traditional types of grating spectrometer become inefficient or unwieldy when adapted to stellar spectroscopy onboard a spacecraft. At grazing incidence, the required length of a high-resolution plane-grating spectrometer can easily exceed the length of the telescope feeding it. For these reasons, we have systematically explored ways to introduce a reflection grating into the converging beam formed by a given objective optical system ahead of its first focus. A spectrometer of this type results in an optical train no longer than the telescope’s existing prime-focus beam.
A new geometric scheme translates a diffraction grating along the straight central groove of an e... more A new geometric scheme translates a diffraction grating along the straight central groove of an exponentially curved pattern. Lit by a stationary incident beam, the two-dimensional pattern scales isotropically, scanning wavelength without change to any angles, macroscopic distances, curvatures or aberrations. This is exemplified by a new class of self-focused grating monochromator, analyzed by rigorous light-path expansion and numerical raytracing. All spectral aberrations in pure meridional powers (including defocus, coma and spherical aberration) cancel for any choice of angular deviation, magnification and translation range. The residual mixed powers yield Δλ/λ = 10<sup>-3</sup> ~ 10<sup>-5</sup> in the soft x-ray for plane and concave gratings at grazing incidence. Over the visible spectrum, Δλ/λ ~ 10<sup>-4</sup>is shown for plane gratings mounted at Littrow and at normal incidence in reflection or transmission.
High resolution M/sub 4,5/ (3d ..-->.. 4p) x-ray emission spectra from a krypton plasma were m... more High resolution M/sub 4,5/ (3d ..-->.. 4p) x-ray emission spectra from a krypton plasma were measured using a recently developed grazing-incidence reflection-grating monochromator/spectrometer with very high flux rates at extreme ultraviolet and soft x-ray wave lengths. The nominal resolving power of the instrument, E/..delta..E, is about 300 in this energy range (approx.80 eV). Three dipole-allowed 3d ..-->.. 4p emission lines were observed at 80.98 eV, 80.35 eV and 79.73 eV. A broad peak at about 82.3 eV is tentatively assigned to transitions resulting from Kr/sup 2 +/, and effects of excitation energy on M/sub 4,5/ x-ray emission were observed. 9 refs., 3 figs., 1 tab.
We have mapped CO emission over a 5° x 5° area in the Cains Major OB1/R1 region. Most of the em... more We have mapped CO emission over a 5° x 5° area in the Cains Major OB1/R1 region. Most of the emission is confied to an elliptical region of approximately 90 x 60 pc. Several CO emission peaks appear, many associated with reflection nebulae. While most of the emission falls in the LSR velocity range 10--20 km sâ»Â¹, we find some material over the full velocity covered (-30 to +45 km sâ»Â¹). There is no simple pattern that would indicate a single expanding shell, but the observations are consistent with the idea that some energetic process, which took place in an initially inhomogeneous cloudy medium, was responsible for the observed morphology of the region. Simple arguments suggest that a supernova explosion is the most likely candidate for this energetic process. The relationship between the process that shaped the clouds and star formation in the region is discussed.
This patent describes a spectrometer optical system employed in combination with a source of elec... more This patent describes a spectrometer optical system employed in combination with a source of electromagnetic radiation and reception means. It comprises: a first concave mirror receiving electromagnetic radiation from the source and reflecting the electromagnetic radiation within a first plane; a second concave mirror receiving the electromagnetic radiation reflected from the source and reflecting the electromagnetic radiation to converge in a second plane. The first and second planes being substantially orthogonal relative to each other; a diffraction grating receiving the converging electromagnetic radiation from the source and producing a spectrum for capture by the reception means; and means for rotating the diffraction grating about an axis relative to the diffraction grating.
An optical system and method comprising a diffraction grating which rotates about its surface nor... more An optical system and method comprising a diffraction grating which rotates about its surface normal to change the magnitude of the wavelength diffracted to an image location. At grazing incidence, such a rotation is determined to maintain the diffracted image in focus over a wide range in scanned wavelength. Monochromator and spectrometer embodiments include plane and curved surface gratings with both classical and varied-spaced groove patterns, and a variety of illumination geometries. In the simplest case, a grazing incidence monochromator is constructed in which a self-focusing classical spherical grating scans the value in wavelength which is transmitted between fixed slits located on the Rowland circle of the grating. The diffracted image remains in perfect focus over two octaves in wavelength at high efficiency, with both entrance and exit slits fixed in position, and the radiation aperture is constant.
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