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Results for “X-ray identification”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS1973

Solar flare line emission between 6 A and 25 A

A list of emission lines in the spectra of solar flares between 6 and 25 A has been compiled using data obtained with a KAP crystal spectrometer on the OSO-5 satellite. The emission lines have been classified according to their sensitivity to flare activity. This classification provides a method for discriminating between iron in high stages of ionization (Fe XX-Fe XXV) and lower stages (Fe XVII-Fe XIX), the lines of which are both present in the same spectral region during flares. Identifications consistent with these classifications are proposed. Anomalous intensities in the spectra of Fe XVII and Fe XX are pointed out, and implications of the observations for models of the X-ray emitting regions are discussed.

Neupert, W. M.↗
NASA NTRS1978

Pattern recognition methods and air pollution source identification

Directional air samplers, used for resolving suspended particulate matter on the basis of time and wind direction were used to assess the feasibility of characterizing and identifying emission source types in urban multisource environments. Filters were evaluated for 16 elements and X-ray fluorescence methods yielded elemental concentrations for direction, day, and the interaction of direction and day. Large numbers of samples are necessary to compensate for large day-to-day variations caused by wind perturbations and/or source changes.

Leibecki, H. F.↗
NASA NTRS1974

OSO-7 observations of a high-latitude X-ray source associated with Abell cluster A2052

An X-ray source with a flux of 1.6 times 10 to the -10th power ergs per sec/sq cm (2-10 keV) has been observed at high galactic latitude by the MIT X-ray detectors on the OSO-7 satellite. Designated GX 8+50, its position is 15 hr 14.2 min right ascension, 6 deg 51 min declination, with a 90 percent confidence error circle of area 0.5 sq deg. The data are consistent with a power-law spectrum with an exponent 1.2 (plus or minus 0.2) or a thermal-bremsstrahlung spectrum with kT = 4 plus or minus 1 keV. A likely identification is the Abell cluster A2052, whose center coincides with the radio source 3C 317.

Heinz, C. J.↗
NASA NTRS1976

MX 1313+29 - A compact source of very low energy X-rays in Coma Berenices

A compact X-ray source near the North Galactic Pole has been detected with the low-energy X-ray telescope aboard the SAS-3 satellite. The spectral temperature of the source is less than 1 million K, and the energy flux at the earth is 3 by 10 to the -10th power erg/sq cm/sec above 0.1 keV. The flux appeared to be constant both on short time scales (10-1000 s), and over the interval from the first SAS-3 observation (June 12, 1975) to the latest (July 15, 1975). The possible identification of this source with the hot white dwarf HZ 43 is discussed.

Hearn, D. R.↗
NASA NTRS1976

Advances in gamma-ray burst astronomy

The paper reviews the current status of observational research into the highly puzzling problem of cosmic gamma-ray bursts. Up to now there is no convincing temporal or spatial correlation with any known celestial processes or objects. The typical burst source strength is somewhere between 10 to the 26th power ergs and 10 to the 52nd power ergs. A list of 39 confirmed and 9 unconfirmed cosmic gamma-ray bursts observed by satellite is given, showing times of occurrence and in some cases, the size in erg per square centimeter. Several approaches to the problem of source object identification are discussed: (1) accumulation of observation statistics with their present poor resolution and research for correlative phenomena, (2) mapping out celestial source distributions with moderate resolution in order to search for galactic or other anisotropies in direction or to look for repeating source regions, and (3) very high-accuracy localization of the source directions of one or several bursts in order to pinpoint a tiny fraction of the celestial sphere for correlative radio, optical and X-ray studies. Planned future instrumentation for deep space probes and multiple-balloon studies is described.

Cline, T. L.↗
NASA NTRS1973

Study for identification of Beneficial Uses of Space (BUS). Volume 2: Technical report. Book 1: Sections 1 through 4

Consolidated information is presented for the study whose purpose was to identify products, processes, and services to be produced in future spacecraft environments for direct utilization on earth. Discussion of methodology for selecting from among potential space processing approaches, definition of requirements for experiments and tests needed to acquire sufficient knowledge for proof testing of selected processes, formulation of research and development schedules to achieve proof testing, and documentation of the decision processes involved in the programs are presented. Technology and programmatics are reported for the following select studies: (1) surface acoustic wave components; (2) transparent oxides; (3) high purity tungsten X-ray targets; and (4) high specificity isoenzymes.

Source record↗
NASA NTRS1976

X-ray nova A0620-00 - Celestial position and low-energy flux

The X-ray nova A0620-00 (Nova Monocerotis 1975) has been observed with the SAS-3 satellite. The 1-10 keV intensity was observed to increase by a factor of 2.3 from August 8 to August 11, 1975. It reached and maintained a constant intensity of 1.7 by 10 to the -6 power erg/sq cm/sec from August 11 to August 13. Limits on periodicities of not more than 2 per cent of the power were obtained for periods from 0.2 ms to 435 s. A precise position was obtained with the SAS-3 modulation collimators on August 15. This led directly to optical and radio identifications. Observations with the SAS-3 low-energy concentrator system on August 27 showed an intense 0.4-0.8 keV flux emanating from the nova. A hydrogen column density of 3.5 (plus or minus 0.3) by 10 to the 21st power per sq cm was inferred from these data.

Doxsey, R.↗
NASA NTRS1967

Mechanized X-ray inspection system for large tanks

Mechanized X ray equipment provides nondestructive inspection of structural weldments at various positions on very large tanks. It mechanizes the placement of the film, automates the identification process, adheres to safety requirements, and eliminates all the usual time-consuming manual operations in industrial radiography.

Occhipinti, G. C.↗
NASA NTRS1972

On the optical identification of Centaurus X-3.

It is suggested that the previously photographed emission-line star WRA 795 is the optical counterpart of Cen X-3, the X-ray pulsar which is a member of an occulting binary system. The star falls in the X-ray error box, which measures only 0.01 square degrees, and shows strong emission variability on a timescale of days, similar to HDE 226868, the suggested Cyg X-1 counterpart.

Margon, B.↗
NASA NTRS1971

X-ray astronomy from sounding rockets at MIT

The research in the program for designing and fabricating payloads for sounding rockets for use in X-ray astronomy is reported. Published papers concerning six Aerobee flights are presented. The results include: (1) the establishment of the radio galaxy M87 as an X-ray source; (2) the studies of the pulsar NPO532, including its X-ray pulse shape, the determination of the synchronism of the optical and X-ray pulses and the codiscovery of its existence as an X-ray pulsar; (3) the determination of many X-ray source positions, and (4) the precise position of Cyg X-1 which led directly to the identification of a ninth magnitude BO supergiant.

Source record↗
NASA NTRS1973

Ultraminiature X-ray fluorescence spectrometer for in-situ geochemical analysis on Mars.

A spectrometer based upon the X-ray fluorescence method of elemental analysis has been developed in an ultraminiature, rugged form suitable for a spacecraft mission to Mars. The instrument employs two radioisotope sources (Fe-55 and Cd-109) which irradiate adjacent areas on a regolith sample. Fluorescent X rays emitted by the sample are detected by four thin-window proportional counters. Using pulse-height discrimination, the energy spectra are determined. Virtually all elements above sodium in the periodic table are detected if present at sufficient levels. Minimum detection limits range from 30 ppm to 2% depending upon the element and the matrix. For most elements, they are below 0.5%. Accuracies also depend upon the matrix, but are generally better than plus or minus 0.5% for all elements of atomic number greater than 14. Elements below sodium are also detected, but as a single group. Ambiguities of identification of the elements producing the observed spectra are minimal.

Clark, B. C.↗
NASA NTRS1975

Centaurus X-3 - New low- and medium-energy X-ray observations

Low- and medium-energy X-ray observations of Cen X-3 during two pointed sounding-rocket experiments are discussed. The lack of low-energy emission from Cen X-3 is consistent with the identification of Krzeminski's star as the optical counterpart of Cen X-3 and normal reddening, in contrast to an earlier measurement by Bleeker et al (1973).

Long, K.↗