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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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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

A liquid radiation detector with high spatial resolution

Detector, using point anode, minimizes problem of oblique tracks by permitting construction of very thin counter. Detector is useful in cosmic ray and high energy physics research and X-ray and neutron diffraction technology.

Alvarez, L.↗
NASA NTRS1972

A gamma ray monitor for the OSO-7 spacecraft.

A NaI(T2) gamma ray spectrometer with a CsI(Na) charged particle and anti-Compton shield has been developed for the spacecraft. The spacecraft telemetry system employs a 800 Hz clock and reads data out on a basic 32-word (byte) Main Frame cycle. The data from the instrument include spectral data, X-ray data, and housekeeping data. The gamma ray pulses from the anode of the central detector flow through the front end electronics, where they are amplified by a charge sensitive preamplifier. The admission of the desired gamma ray into the data stream is controlled by a linear gate.

Higbie, P. R.↗
NASA NTRS1972

Anomalous minima in Cen X-3.

Report of an observation made with a rocket-borne argon-methane proportional counter, which was equipped with a 'Mylar' window and was sensitive to X rays in the range from 0.2 to 10 keV. During a scan of the galactic plane, the detector passed directly over the location of Cen X-3 at a roll rate of 1 deg per second. An extended minimum of X-ray flux was observed. It is concluded that the anomalous effect is intrinsic to the source.

Margon, B.↗
NASA NTRS1973

Multiwire proportional chamber development

The development of large area multiwire proportional chambers, to be used as high resolution spatial detectors in cosmic ray experiments is described. A readout system was developed which uses a directly coupled, lumped element delay-line whose characteristics are independent of the MWPC design. A complete analysis of the delay-line and the readout electronic system shows that a spatial resolution of about 0.1 mm can be reached with the MWPC operating in the strictly proportional region. This was confirmed by measurements with a small MWPC and Fe-55 X-rays. A simplified analysis was carried out to estimate the theoretical limit of spatial resolution due to delta-rays, spread of the discharge along the anode wire, and inclined trajectories. To calculate the gas gain of MWPC's of different geometrical configurations a method was developed which is based on the knowledge of the first Townsend coefficient of the chamber gas.

Doolittle, R. F.↗
NASA NTRS1973

Skylab experiments. Volume 1: Physical science, solar astronomy

The basic subject of this volume is the solar astronomy program conducted on Skylab. In addition to descriptions of the individual experiments and the principles involved in their performance, a brief description is included of the sun and the energy characteristics associated with each zone. Wherever possible, related classroom activities have been identified and discussed in some detail. It will be apparent that the relationships rest not only in the field of solar astronomy, but also in the following subjects: (1) physics - optics, electromagnetic spectrum, atomic structure, etc.; (2) chemistry - emission spectra, kinetic theory, X-ray absorption, etc.; (3) biology - radiation and dependence on the sun; (4) electronics - cathode ray tubes, detectors, photomultipliers, etc.; (5) photography; (6) astronomy; and (7) industrial arts.

Source record↗
NASA NTRS1974

Gamma radiation from the Crab nebula above 35 MeV

Electromagnetic radiation from the Crab nebula were observed, showing that the Crab is unique among strong X-ray sources in that major component in the low energy range (1 to 10 KeV) shows little or no temporal variation. Observations of the Crab above 35 MeV were made with the high energy gamma ray telescope flown on SAS-2. The detector and technique are described in detail.

Kniffen, D. A.↗
NASA NTRS1973

Conical focusing crystal spectrometers for cosmic X-ray astronomy

A crystal spectrometer for rocket and satellite experiments is described. Parallel X rays from a stellar object are reflected at constant angle by Bragg crystals arranged around the sector of a cone so that a single wavelength is brought to a focus onto the axis of the cone. The aberrations produced when this array is tilted to change the wavelength are considered. It is shown that these are minimized by moving cone and detector in a nearly theta to two-theta motion and by using a small-angle sector. In a specific design for a satellite instrument using LiF crystal to observe a spectral region including the iron lines at 1.9 A, a spectral resolution of 3 mA over a spectral range of 1.6-2.1 A can be obtained, with the cosmic-ray background rate, and hence the time to detect a weak line decreased by a factor 80 compared to a flat crystal spectrometer. Examples of performance for a low energy rocket experiment are also given.

Woodgate, B. E.↗
NASA NTRS1974

The UCSD/MIT hard X-ray and low energy gamma ray experiment for HEAO-A

An HEAO-A spacecraft is described which is scheduled for launch in April 1977 to survey the sky in the 0.15 keV to 10 MeV range of X-rays with improved sensitivity and angular resolution. The spectral and time variations of discrete sources, and the spectrum and isotropy of the diffuse component will be measured. A hard X-ray and low energy gamma ray experiment is described which will use as an array of seven (NaI)(Tl)/CsI(Na) phoswich detectors and eight large CsI(Na) shields. Detector events are pulse-height analyzed with a selectable time resolution of 0.1, 0.005, or 0.00002 sec. The instrument background is expected to be comprised of approximately equal parts of diffuse gamma rays entering the aperture, radioactive decay of spallation products, and gamma ray leakage through the shields. Detailed background predictions are presented, and sensitivity estimates indicate that the Crab nebula should be detected up to approximately 5 MeV. Approximate 1% isotropy limits for the diffuse component of cosmic gamma rays should be achieved, and its spectrum measured with improved precision.

Matteson, J. L.↗