Engineering Papers⌕ Search

Engineering topics

Kraushaar, W. L.

Publications and source records attributed to Kraushaar, W. L..

At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Soft diffuse X-rays in the southern galactic hemisphere

A map is presented of the soft X-ray diffuse background flux in the C band (approximately 0.13-0.28 keV) covering almost all of the southern galactic hemisphere. A comparison at constant galactic latitude of both C band and B band (about 0.1-0.18 keV) soft X-ray data with neutral-hydrogen maps shows that the intensity does decrease with increasing neutral-hydrogen column density but in a manner that is inconsistent with photoelectric absorption. It is suggested that the inverse correlation is a displacement effect. X-ray emission regions appear to be where the cool gas is not. Further, the evidence against photoelectric absorption implies that the bulk of the cool gas is beyond the X-ray emitting regions. Fewer than 10 to the 20th power H atoms per sq cm can be between the sun and the X-ray emitting regions. The sun appears to be surrounded by a soft X-ray emission region consisting of gas at a temperature of about 1 million K.

Sanders, W. T.↗
NASA NTRS1977

Three-band observations of the soft X-ray background and some implications of thermal emission models

The galactic component of the very soft diffuse X-ray background in three bands, covering the energy ranges of approximately 100 to 188 eV, 150 to 284 eV, and 500 to 850 eV, is mapped primarily at middle and low galactic latitudes. Intense regions on the maps are identified, and the dissimilarity of the three maps is shown to indicate spectral as well as intensity variations over the sky. Three emission-mechanism models involving hot gas at a single temperature are examined, a multitemperature model is found to be required, and several such models based on hot gas in a steady state or in equilibrium are considered. The problem of overpressure raised by Shapiro and Field (1976) is briefly discussed.

Burstein, P.↗
NASA NTRS1976

A soft X-ray spectrometer for diffuse cosmic sources

The design of a Bragg crystal spectrometer for the diffuse soft X-ray background is described. The instrument has no moving parts; a 6 degree x 20 degree FWHM field of view; resolution in the range 20-100; and spans wavelength ranges 44-80 A or 13-23 A when lead stearate or KAP crystals are used. If placed on a small spacecraft, integration times of approximately 1000 s will be required to detect the existence of the stronger lines expected in the X-ray background.

Borken, R. J.↗
NASA NTRS1975

A search for stellar soft X-ray sources

A sensitive soft X-ray survey of about one-tenth of the sky, carried out as part of the Skylab program and flown on 1973 July 28, revealed no evidence for soft X-ray emission from stellar sources. We present upper limits to the soft X-ray luminosity of about 50 nearby stars. With nominal assumed values for stellar space densities, we show it unlikely that emission from giants, main sequence stars, white dwarfs, or stars in known binary systems can account for the soft X-ray diffuse background.

Vanderhill, M. J.↗
NASA NTRS1974

Coaxial anode improves sensitivity of gas radiation counters

Anode wire itself is enclosed by three segments. Two on ends are rejector segments, and middle one is primary charge-detecting segment. Anode wire is made from tungsten and is surrounded by enamel insulation. Enamel is covered by segments of vapor-deposited gold. At one point in center segment, gold layer makes direct contact with anode wire.

Kraushaar, W. L.↗
NASA NTRS1974

Observation of features in the soft X-ray background flux

Two rocket observations of very soft X-ray diffuse intensity show three emission regions of large angular extent. A large portion of the sky as seen with wide angular resolution is mapped. These three regions coincide with broad regions of small column densities of neutral hydrogen. It is suggested that a component of the interstellar medium is very hot and is responsible for the soft X-ray emission and the O VI.

Williamson, F. O.↗
NASA NTRS1974

Coaxial anode wire for gas radiation counters

The design and characteristics of a gas radiation counter are discussed. The coaxial anode consists of an elongated central wire covered with an electrically insulating sleeve. Several longitudinally discontinuous segments of an electrically conductive coating are disposed about the insulating sleeve in a coaxial pattern along the length of the central wire. The conductive coating segments form a veto or rejection anode at each end of the central wire and a main or primary charge detecting anode between the ends. The segments are coupled together so that the primary charge detecting anode is connected to detection circuitry in anti-coincidence with the veto anodes. Background radiation detected by either of the veto anodes and the primary charge detecting anode is rejected and the sensitivity of the radiation counter device is increased.

Kraushaar, W. L.↗
NASA NTRS1974

Soft X-ray bremsstrahlung and fluorescent line production in the atmosphere by low energy electrons

The effect of low energy quasi-trapped or precipitating electrons which impact on the counter windows of soft X-ray detectors are discussed. The errors caused by X-rays produced in the residual atmosphere above a rocket-borne detector because of the resemblance to X-rays of cosmic origin are examined. The design and development of counter windows which make it possible to identify the atmospherically produced X-rays are described. Curves are presented to show the following: (1) preliminary low energy electron data from Atmospheric Explorer C, (2) X-ray flux in electron-excited nitrogen and oxygen, (3) typical proportional counter response to low energy cosmic rays, and (4) proportional counter response to X-radiation produced by electrons incident upon a gas of oxygen to nitrogen number of 0.4.

Kraushaar, W. L.↗
NASA NTRS1973

X-ray spectrum of the Tycho supernova

Uhuru satellite data combined with Wisconsin rocket data suggest that the X-ray spectrum of the Tycho supernova remnant is composite and includes a thermal as well as a nonthermal component, the latter being an extension of the radio spectrum. Attempts have been made to fit the low-energy observations (thermal component) with the Tucker and Koren calculations for the solar corona.

Coleman, P. L.↗
NASA NTRS1973

Diffuse Cosmic X-rays Below 1 Kev

Measurements of low energy diffuse X-rays are discussed. Particular attention was given to the energy region below 280 eV, the carbon K edge. Spatial structure, nature of local emission, and X-ray extragalactic origin are also discussed.

Kraushaar, W. L.↗
NASA NTRS1973

Coaxial anode for background suppression in X-ray proportional counters.

We have devised, constructed, and tested in flight a scheme which permits the ends (near the anode seals) as well as the bottom and sides of an X-ray astronomy proportional counter to be protected by anticoincidence guard counters. A rocket-borne test has shown that the non-X-ray background is reduced by an additional factor of about 30 when the end guard counter feature is added.

Bunner, A. N.↗
NASA NTRS1973

Observations of spatial structure in the soft X-ray diffuse flux.

Repeated observations of a diffuse source in the region of about 200 deg and +10 deg galactic longitude and latitude, respectively, illustrate the complexity of the low-energy X-ray background. The source is not well correlated with known objects or features, and cannot be explained by geometrically simple models of diffuse emission. The measurements indicate that this emission feature, and by implication a large fraction of the 1/4-keV flux observed in the galactic plane, probably originates outside the solar system.

Bunner, A. N.↗
NASA NTRS1973

Diffuse cosmic X-rays below 1 keV

A description is given of low energy soft diffuse X-ray flux in the energy region below 280 eV, the carbon-K edge. Spatial structure, nature of local emission, and intensity are also discussed.

Kraushaar, W. L.↗
NASA NTRS1972

Soft X-rays from the vicinity of the North Polar Spur.

Soft X rays in the energy regions below 284 eV and between 500 and 1000 eV have been detected on the vicinity of the North Polar Spur. The region of enhanced X-ray emission reported was observed from an Aerobee 150 rocket launched on May 29, 1970, from Woomera, Australia.

Bunner, A. N.↗
NASA NTRS1972

Coaxial anode for background suppression in X-ray proportional counters

A scheme which permits the ends (near the anode seals) as well as the bottom and sides of an X-ray astronomy proportional counter to be protected by anticoincidence guard counters is described. A rocket-borne test showed that the non-X-ray background is reduced by an additional factor of about 30 when the end guard counter feature is added.

Bunner, A. N.↗
NASA NTRS1971

X-ray observation of a new soft source in Cygnus.

The location of the new X-ray source, designated Cygnus X-6, is discussed. The polycarbonate window counter detected Cyg X-6 only in the pulse-height interval from 0.5 to 1.3 keV. A total of 44 counts was acquired from the source above a diffuse X-ray and non-X-ray background of 18 plus or minus 3 counts. The polycarbonate pulse-height spectrum for Cyg X-6 is presented together with the calculated counter response to three different model source spectra.

Coleman, P. L.↗