242 research outputs found
New high-dispersion, high-resolution X-ray spectrometer - Measurements of the chromium K alpha 1 and 2 lines
New high dispersion, high resolution X ray spectromete
A ruggedized thin-window proportional-counter tube
Design and testing of ruggedized, thin window proportional counter tube for detecting X rays in light element
Dual purpose optical instrument capable of simultaneously acting as spectrometer and diffractometer
A dual purpose optical instrument is described capable of simultaneously acting as a spectrometer and diffractometer to respectively perform elemental and structural analysis of an unknown sample. The diffractometer portion of the instrument employs a modified form of Seeman-Bohlin focusing which involves providing a line source of X-rays, a sample, and a detector, all on the same focal circle. The spectrometer portion of the instrument employs a fixedly mounted X-ray energy detector mounted outside of the plane of the focal circle
Cylindrical Crystal Imaging Spectrometer (CCIS) for cosmic X-ray spectroscopy
A "stigmatic" focusing, Bragg crystal spectrometer was developed and used for high spectral resolution X-ray emission line diagnostics on hot laboratory plasmas. The concept be applied at the focal plane of an orbiting X-ray telescope where it offers several advantages over conventional spectrometers, i.e., mechanical simplicity, high resolving power and sensitivity, simultaneous measurement of an extended segment of spectrum, and good imaging properties. The instrument features a simple, unambiguous, non-scanning spectrum readout that is not adversely affected by either spacecraft pointing error or source extent. The performance of the instrument is estimated in the context of the Advanced X-Ray Astrophysical Facility mission
Aluminized thin-window proportional-counter tube is stronger, more responsive in long wavelength region
A thin-window proportional counter tube of 0.25-mil Mylar with a thin aluminum coating on one side permits efficient detection of long wavelength X rays. It is sufficiently rugged for long-term use in space or other demanding environments
Image Reconstruction with a LaBr3-based Rotational Modulator
A rotational modulator (RM) gamma-ray imager is capable of obtaining
significantly better angular resolution than the fundamental geometric
resolution defined by the ratio of detector diameter to mask-detector
separation. An RM imager consisting of a single grid of absorbing slats
rotating ahead of an array of a small number of position-insensitive detectors
has the advantage of fewer detector elements (i.e., detector plane pixels) than
required by a coded aperture imaging system with comparable angular resolution.
The RM therefore offers the possibility of a major reduction in instrument
complexity, cost, and power. A novel image reconstruction technique makes it
possible to deconvolve the raw images, remove sidelobes, reduce the effects of
noise, and provide resolving power a factor of 6 - 8 times better than the
geometric resolution. A 19-channel prototype RM developed in our laboratory at
Louisiana State University features 13.8 deg full-angle field of view, 1.9 deg
geometric angular resolution, and the capability of resolving sources to within
35' separation. We describe the technique, demonstrate the measured performance
of the prototype instrument, and describe the prospects for applying the
technique to either a high-sensitivity standoff gamma-ray imaging detector or a
satellite- or balloon-borne gamma-ray astronomy telescope.Comment: submitted to Nuclear Instrument & Methods, special edition: SORMA
2010 on June 16, 201
A preliminary design study for a cosmic X-ray spectrometer Interim report
Cosmic X ray spectrometer development and testin
XMM-Newton observation of the eclipsing binary Algol
We present an {\sl XMM-Newton} observation of the eclipsing binary Algol
which contains an X-ray dark B8V primary and an X-ray bright K2IV secondary.
The observation covered the optical secondary eclipse and captured an X-ray
flare that was eclipsed by the B star. The EPIC and RGS spectra of Algol in its
quiescent state are described by a two-temperature plasma model. The cool
component has a temperature around 6.4 K while that of the hot
component ranges from 2 to 4.0 K. Coronal abundances of C, N, O,
Ne, Mg, Si and Fe were obtained for each component for both the quiescent and
the flare phases, with generally upper limits for S and Ar, and C, N, and O for
the hot component. F-tests show that the abundances need not to be different
between the cool and the hot component and between the quiescent and the flare
phase with the exception of Fe. Whereas the Fe abundance of the cool component
remains constant at 0.14, the hot component shows an Fe abundance of
0.28, which increases to 0.44 during the flare. This increase is
expected from the chromospheric evaporation model. The absorbing column density
of the quiescent emission is 2.5 cm, while that of
the flare-only emission is significantly lower and consistent with the column
density of the interstellar medium. This observation substantiates earlier
suggestions of the presence of X-ray absorbing material in the Algol system.Comment: 15 pages, 9 figures, Accpted by RA
Precise location of Sagittarius X ray sources with a rocket-borne rotating modulation collimator
Precise location of Sagittarius X ray sources with rocket-borne rotating modulation collimato
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