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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Refining Methods to Determine the Isotopic Composition of Uranium Particles by Laser Ablation MC-ICP-MS

We report on efforts to mitigate the generation of isotopic anomalies during the ablation of micrometer-sized uranium oxide particles and analysis by MC-ICP-MS. The results of testing on particles of U200 indicate that laser fluence and frequency can affect isotopic data produced by laser ablation, but no settings were tested that could eradicate the signal spiking effect and generation of anomalous isotopic data for 234U/238U and 236U/238U. These anomalies are more frequent in samples with higher 235U enrichments, which is expected given their higher abundances of 234U and 236U. Of the standards tested here, only U005-A was anomaly-free. Efforts to compare the laser traces for particles with normal and anomalous isotopic compositions showed subtle differences in the behavior of the 234U/238U and 236U/238U ratios. However, it would be challenging to identify anomalous data points from a population of unknowns using this distinction, i.e., this is unlikely to be diagnostic. Thus, using current analytical hardware, we cannot eradicate the signal spiking phenomenon and cannot unambiguously identify isotopic anomalies from laser ablation traces. Ultimately, laser ablation ICP-MS would either require dramatic improvement to the ablation process and generation of more homogenous aerosols and/or improvements to detector electronics to identify and correct for the spiking phenomenon. Even if the reliability of the technique could be improved, a broader question to address is whether current data quality is of a high enough standard for laser ablation MC-ICP-MS to be used as a complementary technique to LG-SIMS for Safeguards.

organic↗
NASA NTRS1965

Electromagnetic flowmeter.

Transducer and electronic detector of electromagnetic flow meter for volumetric flow measurement for both electrically conducting and dielectric fluids

FLOW METER↗
NASA NTRS1972

Type 3 solar radio bursts

Using low frequency satellite observations, a direct comparison of the different theories is possible of the structure of the interplanetary medium. Measurements were made by satellite electron detectors in the same region of the interplanetary media where rapid drift type 3 solar radio bursts are generated. Results show, on the basis of this comparison, the general inadequacies of current type 3 burst theories and indicate a needed emphasis on formulating a new theory that is consistent with the low frequency observations. Representative observations from the RAE satellite are shown. The brightness temperature, which is a measure of the energy flux, versus frequency was plotted. Two events, a large burst and a large storm are also shown, each recorded at frequencies of 2.8 MHz and 700 KHz. High frequency curves obtained from ground-based observations are given.

Evans, L. G.↗
NASA NTRS1974

Chemical composition of cosmic rays with Z greater than or equal to 30 and E greater than or equal to 325 MeV/N

Results are presented on the chemical composition of VVH cosmic rays from a series of six high-altitude balloon flights of a large-area, high-resolution electronic detector. The charge composition in the 32 less than or equal to Z less than or equal to 45 interval is found to be inconsistent with S-process nucleosynthesis. The energy spectrum of particles with Z greater than or equal to 32 between 600 and 1500 MeV/N at the top of the atmosphere is measured and is found to be consistent with the 25 less than or equal to Z less than or equal to 27 group within experimental error.

Binns, W. R.↗
NASA NTRS1977

Advanced Atmospheric Sounder and Imaging Radiometer (AASIR)

Design information for the Advanced Atmospheric Sounder and Imaging Radiometer is reported, which was developed to determine the configuration of a sensor for IR and visible imaging. The areas of technology reported include: systems design, optics, mechanics, electronics, detectors, radiative cooler, and radiometric calibration.

Source record↗
NASA NTRS1978

The High Energy Astronomy Observatory X-ray Telescope

The High Energy Astronomy Observatory-Mission B (HEAO-B) is a satellite observatory for the purpose of performing a detailed X-ray survey of the celestial sphere. Measurements will be made of stellar radiation in the range 0.2 through 20 keV. The primary viewing requirement is to provide final aspect solution and internal alignment information to correlate an observed X-ray image with the celestial sphere to within one-and-one-half arc seconds. The Observatory consists of the HEAO Spacecraft together with the X-ray Telescope. The Spacecraft provides the required attitude control and determination system, data telemetry system, space solar power system, and interface with the launch vehicle. The X-ray Telescope includes a high resolution mirror assembly, optical bench metering structure, X-ray detectors, detector positioning system, detector electronics and aspect sensing system.

Miller, R.↗
NASA NTRS1979

Cosmic-ray abundances of individual elements in the Z interval between 26 and 30

The relative abundances of Fe, Co, Ni, Cu, and Zn in the cosmic rays have been measured using a large-area balloon-borne electronic detector system. The abundance ratios Ni/Fe and Zn/Fe are 5.0 + or - 0.2% and 0.06 + or - 0.01%, respectively. The Zn abundance is low (40%) compared with the Cameron (1973) (C1) solar system, and is best consistent with the solar system C2 meteorite abundances. The ratios Co/Fe and Cu/Fe, extrapolated to the top of the atmosphere, are 0.68 + or - 0.14% and 0.066 + or - 0.030% respectively; since charge peaks are not resolved at Co and Cu, these results are taken as upper limits of 0.8% and 0.1%, respectively. The Co upper limit is consistent with complete decay of Co-57 at the source and implies a lower limit of 2 years for the time between nucleosynthesis and acceleration of these nuclei.

Tueller, J.↗
NASA NTRS1980

Crossed-grid charge locator

Circuit locates center of cloud of charge on wire grid to within 6.5 micrometers. Wires in vicinity of charge cloud develop voltages that are processed by priority encoders to develop coarse and fine position codes. Device is used with microchannel plate amplifier in X-ray photon detectors, electron microscopes, and closed-circuit television.

Harrison, D. C.↗
NASA NTRS1979

Faint-object spectrograph for Space Telescope

The paper presents the Faint Object Spectrograph (FOS) for the Space Telescope to provide a digitized spectra of faint astronomical objects over the 115 to 700 nm wavelength range at resolving powers of 1000 and 100. A variety of concave gratings and prisms is employed to form nearly stigmatic spectra on one of the two Digicon photon counting detectors which are optimized for two different but overlapping ranges. The scientific goals associated with quasars, active galaxies, and objects within our solar system are discussed, and the FOS optical design features, including detectors, electronics, signal processing, power supplies, and data handling are examined. The FOS structural system, mechanism, and controls are described, along with the predicted performance capabilities in the spectral and spectropolarimetry modes. Finally, system performance parameters, including spatial resolution, time resolution, noise, and efficiency are discussed.

Harms, r. J.↗
NASA NTRS1980

Focal-plane optimization for detector noise limited performance in cryogenic Fourier transform spectrometer /FTS/ sensors

A study was performed to determine the optimum focal plane configuration including optics, filters and detector-preamplifier selection. The configuration was optimized particularly with respect to minimizing the noise level, but fabrication considerations for a cryogenic environment were also taken into account. The noise terms from source, background, detector electronics and charged particle radiation were quantitatively evaluated. It appears that noise equivalent spectral radiance less than 10 to the -11th W/sq cm per sr per kayser can be achieved between 2.5 and 20 microns.

Mcguirk, M.↗
NASA NTRS1982

Study of photoconductive indium antimonide

Indium antimonide (InSb) material was assessed for use as photoconductive infrared detectors under low background conditions. Such detectors must be more rugged, and have lower capacitance, than the common photovoltaic InSb detector. Electronic grade n-type InSb was etched to 50 micrometers thickness, and tin and gold contacts were applied by evaporation. The test devices showed a relatively low ultimate impedance: 7 Mohms at 4.2 K. This was attributed to the presence of impurity levels of very shallow energies, and this material was judged unsuitable for low background detection.

Low, F. J.↗
NASA NTRS1983

Experimental limits of the extreme ultraviolet background

Photometric observations of the diffuse extreme ultraviolet background with two photometers having bandpasses of 750-940 A and 1040-1080 A are reported. The payload, which was flown aboard an ARIES sounding rocket in June 1982, is described, including the electron detectors, filters, and calibration. The operation of the probe during the experiment, including its motions, are described. The primary experiment involved spectroscopic observation of the hot white dwarf HZ43. The photometer count rate is shown and the measurements of the diffuse background are compared with theoretical predictions. Despite the lower limits obtained using a narrowband detector, the measurements are not sensitive enough to draw any relevant astrophysical conclusions.

Wulf-Mathies, C.↗