scholarly journals A Rocket-Borne X-Ray Spectrometer/Monochromator System for Mapping the Solar Corona

1971 ◽  
Vol 41 ◽  
pp. 181-181
Author(s):  
L. W. Acton ◽  
R. C. Catura ◽  
J. L. Culhane ◽  
A. J. Meyerott
Keyword(s):  
Spatial Distribution ◽  
Solar Corona ◽  
Proportional Counter ◽  
Line Emission ◽  
Field Of View ◽  
The Sun ◽  
X Ray ◽  
Rocket Flight

A rocket payload is being prepared for the purpose of examining the spatial distribution of line emission from two important ions, Ovii and Neix, in the solar corona. The payload will contain the following integrated set of instruments.(1) A pair of X-ray spectrometers utilizing KAP crystals of approximately 100 cm2 area.(2) An optical aspect camera with a 1 Å bandpass H-α filter to measure the location of the field of view of the X-ray systems on the sun through out the rocket flight.(3) A collimated proportional counter spectrometer operating in the 3 to 15 keV range.

Impulsive X-ray Emission by the Sun

1967 ◽  
Vol 1 (2) ◽  
pp. 51-52
Author(s):  
J. R. Harries
Keyword(s):  
Proportional Counter ◽  
Spin Axis ◽  
Field Of View ◽  
The Sun ◽  
Full Width ◽  
X Ray ◽  
Beryllium Window ◽  
Window Area ◽  
Satellite Spin

Solar X-ray bursts have been observed by a xenon-methane filled proportional counter on the satellite IMP-F. The counter is one inch deep and has a 14 mg/cm2 beryllium window. A slat collimator restricts the field of view to a full width of 5° in the direction of the satellite spin while allowing the counter to see ±60° in the plane containing the spin axis. The effective window area of the counter is 2.2 cm2, after allowing for the collimator.

Crystal spectrometry of active regions on the Sun

1973 ◽  
Vol 334 (1597) ◽  
pp. 231-239 ◽  
Keyword(s):  
Line Emission ◽  
Active Regions ◽  
Field Of View ◽  
Sounding Rocket ◽  
The Sun ◽  
Crystal Spectrometer ◽  
Isothermal Model ◽  
X Ray ◽  
Solar Observations ◽  
History Of

A crystal spectrometer has been flown on a sounding rocket to study the soft X-ray line emission from the sun. Collimators, with a field of view 9 arc min square, allowed individual active regions to be observed. A detailed description of the instrument is given. Solar conditions at the time of launch are then discussed, together with a brief history of the three active regions studied. It is shown that the collimators performed satisfactorily. The spectrum of an active region is used to identify the important solar line emission, and a comparison of the spectra obtained near 1.7 nm is made. The temperatures of the regions are discussed, and it is shown that a non-isothermal model is required. A good correlation is found between the soft X-ray emission and other solar observations.

scholarly journals Silicon in the solar corona

1965 ◽  
Vol 23 ◽  
pp. 115-123
Author(s):  
K. G. Widing ◽  
J. R. Porter
Keyword(s):  
Solar Corona ◽  
Relative Intensity ◽  
Line Emission ◽  
X Ray ◽  
Resonance Transitions ◽  
Spectral Ranges

Resonance lines of coronal ions of silicon are prominent in the spectral ranges 40–62 Å and 254–356 Å.An unexpected feature of the soft X-ray spectrum is the weakness or absence of the resonance lines of iron in ionization stages XI through XV.A second feature is the prominence of lines of the type (3d → 2p) relative to the resonance transitions (3p → 2s) in Li-like and Beryllium-like spectra. It is suggested that the upper levels (3d) are excited by quadrupole collisions from the ground 2s or 2s2levels.The intensity of the soft X-ray lines relative to the resonance lines in the 300 Å region seems to be more consistent with temperatures well above one million degrees than with temperatures as low as 700000°K, but the data are not adequate for a precise comparison. The relative intensity of the line emission from the various stages of silicon ionization may be interpreted as indicating that the ionization of silicon peaks in stages IX and X.The abundances of C, Mg, S, and Al relative to silicon do not seem to be greatly different from the chromospheric abundances reported by Pottasch or with the photospheric abundances.

A Discussion on the physics of the solar atmosphere - Spectroscopic studies of the solar corona at x-ray wavelengths

1976 ◽  
Vol 281 (1304) ◽  
pp. 383-390 ◽  
Keyword(s):  
Spatial Distribution ◽  
Solar Corona ◽  
Spatial Variation ◽  
Resonance Line ◽  
Active Regions ◽  
Resonance Scattering ◽  
Spectroscopic Studies ◽  
Line Of Sight ◽  
X Ray ◽  
Forbidden Transitions

The spatial distribution of the emission in several X-ray lines is discussed with emphasis on temperature dependence and association with active regions. New results are presented for the trio of helium-like O vii lines which demonstrate (1) a spatial variation in the density dependent forbidden to intersystem line ratio, and (2) a strong spatial variation in the intensity of the O vii resonance line relative to the optically forbidden transitions. The second effect appears to be caused by resonance scattering by material in the line of sight.

scholarly journals Highly Ionized sodium X-ray line emission from the solar corona and the abundance of sodium

2010 ◽  
Vol 518 ◽  
pp. A41 ◽  
Author(s):  
K. J. H. Phillips ◽  
K. M. Aggarwal ◽  
E. Landi ◽  
F. P. Keenan
Keyword(s):  
Solar Corona ◽  
Line Emission ◽  
X Ray

A scanning X-ray spectroheliograph

1970 ◽  
Vol 317 (1528) ◽  
pp. 101-112 ◽  
Keyword(s):  
Proportional Counter ◽  
Grazing Incidence ◽  
The Sun ◽  
Design And Development ◽  
X Ray ◽  
Preliminary Results

A grazing incidence reflector which focuses radiation on to a proportional counter has been used to obtain X -ray pictures of the Sun in a number of relatively narrow wavelength bands below 2 nm. The design and development of the instrument is discussed together with the preliminary results from two rocket flights.

scholarly journals Monochromatic X-Ray Imagers of the Sun Based on the Bragg Crystal Optics

2021 ◽  
Vol 8 ◽  
Author(s):  
Anton A. Reva ◽  
Sergey V. Kuzin ◽  
Alexey S. Kirichenko ◽  
Artem S. Ulyanov ◽  
Ivan P. Loboda ◽  
...  
Keyword(s):  
Solar Activity ◽  
Solar Corona ◽  
Spectral Lines ◽  
Coronal Plasma ◽  
The Sun ◽  
Spectral Filter ◽  
Crystal Optics ◽  
X Ray ◽  
Hot Plasma ◽  
Wide Range

Investigations of solar activity require information about plasma in a wide range of temperatures. Generally, researchers require observations from telescopes producing monochromatic images of coronal plasma with cool, warm, and hot temperatures. Until now, monochromatic telescopic imaging has been made only in the Mg XII 8.42 Å line with the Mg XII spectroheliograph on board CORONAS-I, CORONAS-F, and CORONAS-PHOTON satellites. The Mg XII spectroheliograph used Bragg crystal optics. Its design is based on two main principles: (1) to select the working wavelength and the crystal in such a way that reflection occurs at small incident angles; (2) to use the aperture of the mirror as a spectral filter. We believe that these design principles can be applied to other spectral lines. In this article, we will review the design of the Mg XII spectroheliograph and present our thoughts on how to apply these principles to the Si XIV 6.18 Å and Si XIII 6.65 Å lines. A combination of the monochromatic Mg XII 8.42 Å, Si XIV 6.18 Å, and Si XIII 6.65 Å images will help us to study the dynamics of the hot plasma in the solar corona.

scholarly journals Small-Scale Fluctuations and Anisotropies in the 1–3 keV X-Ray Background

1990 ◽  
Vol 139 ◽  
pp. 408-409
Author(s):  
X. Barcons ◽  
A. C. Fabian
Keyword(s):  
Spatial Distribution ◽  
Probability Distribution ◽  
Proportional Counter ◽  
Flux Distribution ◽  
Small Scale ◽  
X Ray ◽  
Deep Survey ◽  
X Ray Background ◽  
Einstein Observatory ◽  
Source Number

The spatial distribution of the 1–3 keV X-ray background (XRB) in five Einstein Observatory Imaging Proportional Counter fields has been analyzed. The autocorrelation function does not exceed 9% on scales ~5′. The observed count probability distribution is then used to check the source number-flux distribution at faint levels. Agreement with the Einstein Observatory deep survey is obtained. A cutoff in the number-flux distribution for a Euclidean population of sources at a flux approximately one-half of the deep survey limit, previously suggested by Hamilton and Helfand (1987), is also inferred.

scholarly journals A Search for the Signature of the Diffuse Soft X-ray Background in the ROSAT Wide-Field Camera All-Sky Survey

1996 ◽  
Vol 152 ◽  
pp. 289-293
Author(s):  
R.G. West ◽  
R. Willingale ◽  
J.P. Pye ◽  
T.J. Sumner
Keyword(s):  
Charged Particles ◽  
Field Of View ◽  
Wide Field ◽  
Galactic Latitude ◽  
The Sun ◽  
X Ray ◽  
Cosmic Background ◽  
Sky Survey ◽  
Cosmic Abundance ◽  
X Ray Background

We present the results of an attempt to locate the signature of the diffuse soft X-ray background in the ROSAT Wide-Field Camera (WFC) all-sky survey. After removal of non-cosmic background sources (eg. energetic charged particles), the field-of-view integrated count rate in the WFC S1a filter (90–185 eV) shows no consistent variation with Galactic latitude or longitude. We place limits on the signal from the soft X-ray background (SXRB) in the WFC, and show that these limits conflict with the observations of the Wisconsin Sky Survey if the SXRB in this energy range is assumed to be produced by a thermal plasma of cosmic abundance and a temperature T ~ 106 K within d ~ 100 pc of the Sun.

scholarly journals X-Ray Observations of M87’s Halo

1980 ◽  
Vol 5 ◽  
pp. 689-693
Author(s):  
D. Fabricant ◽  
M. Lecar ◽  
P. Gorenstein
Keyword(s):  
Proportional Counter ◽  
Total Mass ◽  
Precise Determination ◽  
Virgo Cluster ◽  
Field Of View ◽  
Two Dimensional ◽  
X Ray ◽  
Einstein Observatory ◽  
Extended Emission

We briefly describe the soft X-ray image of M87 obtained using the imaging proportional counter aboard the Einstein Observatory. These data provide further strong evidence for the existence of a massive halo of dark matter surrounding M87 and allow a much more precise determination of its mass. Two pointing positions of the satellite were analyzed; one centered on M87, the other 63’ south and 25’ east of M87. The field of view of the imaging proportional counter is 60’ × 60’, and it attains a two dimensional spatial resolution of ˜ 1.5’ in a spectral range spanning 0.1 to 4.5 keV.As previous reports had suggested (Gorenstein et al. 1977; Fabricant et al. 1978), the present observations show M87 to be a strong, very extended, thermal X-ray source with a temperature near 2 keV, surrounded by weaker and still more extended emission from hotter gas associated with the Virgo cluster as a whole (Davison, 1978; Lawrence, 1978). We find M87 to have a total 0.5-4.5 keV X-ray luminosity of about 2 × 1043 ergs/sec, and an extrapolated 2-6 keV luminosity of approximately 1 × 1043 ergs/sec. The total mass of gas inferred from the X-ray measurement exceeds 1012 solar masses.

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