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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

The case for a burst from 3U 0614+09

A single flare event with a rise time of about 7 s and a decay time of approximately 40 s was observed by the Goddard cosmic X-ray spectroscopy experiment on OSO-8 during observations of 3U 0614+09 in September 1975. The possibility is discussed that the source was 3U 0614+09, which has been compared with the low-mass binary Sco X-1. The spectra during the event could be fitted with blackbody (kT = 0.8-1.1 keV) or thermal bremsstrahlung (kT = 1.1-2.5 keV) models with absorption by cool material. In the blackbody model the source was of the order of 1 million cm in size.

Swank, J. H.↗
NASA NTRS1978

A 4.8 hour periodicity in the spectra of Cygnus X-3

The X-ray binary Cyg X-3 has been observed on three occasions during 1975 and 1976 by the GSFC Cosmic X-Ray Spectroscopy Experiment on OSO 8. The X-ray spectra from all three observations can be represented by power-law continua with strong iron line emission. Comparisons of spectra taken within the same observation at various phases of the 4.8 hour period reveal a relative excess of low-energy X-ray emission near zero phase (i.e., the minimum) of the 4.8 hour modulation. In addition, the centroid of the line emission is observed to vary in phase with the 4.8 hour cycle. The possibility of persistent thermal X-ray emission from material surrounding the binary system is introduced in an effort to account for the observed effects.

Becker, R. H.↗
NASA NTRS1979

X-ray spectra of X Persei

The GSFC cosmic X-ray spectroscopy experiment on OSO 8 observed X Per for 20 days during two observations in 1976 February and 1977 February. The spectrum of X Per varies in phase with its 13.9 minute period, hardening significantly at X-ray minimum. Unlike other X-ray binary pulsar spectra, those of X Per do not exhibit iron line emission or strong absorption features. Our data show no evidence for a 22 hour periodicity in the X-ray intensity of X Per. These results indicate that the X-ray emission from X Per may be originating from a neutron star in a low-density region far from the optically identified Be star.

Becker, R. H.↗
NASA NTRS1984

Balloon test project: Cosmic Ray Antimatter Calorimeter (CRAC)

Cosmic ray observations from balloon flights are discussed. The cosmic ray antimatter calorimeter (CRAC) experiment attempts to measure the flux of antimatter in the 200-600 Mev/m energy range and the isotopes of light elements between 600 and 1,000 Mev/m.

Christy, J. C.↗
NASA NTRS1989

Abundances of ultraheavy elements in the cosmic radiation - Results from HEAO 3

An analysis is presented that, for the first time, systematically normalizes the data from the HEAO 3 heavy nuclei experiment on the cosmic-ray abundances of all the elements heavier than germanium to that of iron. In the range of atomic number Z from 33 to 60, the analysis yields abundances of odd-even element pairs. The abundances are consistent with a cosmic-ray source having a composition similar to that of the solar system, but subject to source fractionation correlated with the first ionization potential (FIP) of each element. For Z greater than 60, the analysis yields abundances of element groups. For these heaviest nuclei, we find an enhancement of the abundance of the platinum group, elements with Z of 74-80, relative to that in propagated solar system source, and a corresponding increase in the abundance of the largely secondary elements in the 62-73 range. These abundances suggest that there is an enhancement of the r-process contribution to the source nuclei in the Z greater than 60 charge region. Over the entire region of charge, standard leaky box models of propagation satisfactorily model secondary production.

Binns, W. R.↗
NASA NTRS1995

High Energy Antimatter Telescope (HEAT) Balloon Experiment

This grant supported our work on the High Energy Antimatter Telescope(HEAT) balloon experiment. The HEAT payload is designed to perform a series of experiments focusing on the cosmic ray positron, electron, and antiprotons. Thus far two flights of the HEAT -e+/- configuration have taken place. During the period of this grant major accomplishments included the following: (1) Publication of the first results of the 1994 HEAT-e+/- flight in Physical Review Letters; (2) Successful reflight of the HEAT-e+/- payload from Lynn Lake in August 1995; (3) Repair and refurbishment of the elements of the HEAT payload damaged during the landing following the 1995 flight; and (4) Upgrade of the ground support equipment for future flights of the HEAT payload.

Beatty, J. J.↗
NASA NTRS2001

Performance of the Advanced Thin Ionization Calorimeter (ATIC)

The ATIC instrument is a balloon-borne experiment capable of measuring cosmic ray elemental spectra from 50 GeV to 100 TeV for nuclei from H to Fe with a fully active Bismuth Germanate calorimeter. Several Long Duration Balloon flights from McMurdo station, Antarctica are scheduled. The detector was tested with high energy electron, proton, and pion beams at CERN. We present results for 150 and 375 GeV protons, and 150 GeV pions and comparison with a GEANT Monte Carlo.

Case, G.↗
NASA NTRS2016

Cross Section Calculations and Comparison to Experiment

Understanding fragmentation of galactic cosmic ray nuclei in collisions within spacecraft structures and human tissues is an important element in assessing biological risk to crew members from this radiation source. Over the past four decades, various models have been developed to describe these important processes. Some models invoke semi-classical concepts based upon geometric descriptions of collisions between spherical nuclei.

Townsend, L. W.↗
NASA NTRS1995

Time correlations between low and high energy gamma rays from discrete sources

Activities covered the following areas: (1) continuing analysis of the Cygnus Experiment data on the shadowing of cosmic rays by the moon and sun, which led to a direct confirmation of the angular resolution of the CYGNUS EAS array; and (2) development of analysis methods for the daily search overlapping with EGRET targets. To date, no steady emission of ultrahigh energy (UHE) gamma rays from any source has been detected by the Cygnus Experiment, but some evidence for sporadic emission had been found. Upper limits on steady fluxes from 49 sources in the northern hemisphere have been published. In addition, a daily search of 51 possible sources over the interval April 1986 to June 1992 found no evidence for emission. From these source lists, four candidates were selected for comparison with EGRET data.

Ellsworth, R. W.↗
NASA NTRS1982

The HEAO-3 Cosmic Ray Isotope spectrometer

This paper describes the Cosmic Ray Isotope instrument launched aboard the HEAO-3 satellite on September 20, 1979. The primary purpose of the experiment is to measure the isotopic composition of cosmic ray nuclei from Be-7 to Fe-58 over the energy range 0.5 to 7 GeV/nucleon. In addition charge spectra will be measured between beryllium and tin over the energy range 0.5 to 25 GeV/nucleon. The charge and isotope abundances measured by the experiment provide essential information needed to further our understanding of the origin and propagation of high energy cosmic rays. The instrument consists of 5 Cerenkov counters, a 4 element neon flash tube hodoscope and a time-of-flight system. The determination of charge and energy for each particle is based on the multiple Cerenkov technique and the mass determination will be based upon a statistical analysis of particle trajectories in the geomagnetic field.

Bouffard, M.↗
NASA NTRS2002

Precise Measurements of the Cosmic Ray Antiproton Spectrum with BESS Including the Effects of Solar Modulation

The Balloon Borne Experiment with a Superconducting Spectrometer (BESS) has measured the energy spectrum of cosmic-ray antiprotons between 0.18 and 4.20 GeV in eight flights between 1993 and 2002. Above about 1 GeV, models in which antiprotons are secondary products of the interactions of primary cosmic rays with the interstellar gas agree with the BESS antiproton spectrum. Below 1 GeV, the data show a possible excess antiproton flux compared to secondary model predictions, suggesting the presence of an additional source of antiprotons. The antiproton/proton ratios measured between 1993 and 1999, during the Sun's positive-polarity phase, are consistent with simple models of solar modulation. However, results from the 2000 flight, following the solar magnetic field reversal, show a sudden increase in the antiproton/proton ratio and tend to favor a charge-sign-dependent drift model. To extend BESS measurements to lower energies, an evolutionary instrument, BESS-Polar, is under construction for polar flight in 2004.

Mitchell, J. W.↗
NASA NTRS1985

Measurement of low energy cosmic rays aboard Spacelab-1

In December 1983 the first Spacelab mission was launched for a duration of 10 days. Aboard was the Kiel experiment Isotopic Stack designed for measurement of heavy cosmic ray nuclei with nuclear charge equal to or greater than 3 and energies up to some 100MeV/nuc. One part of the stack was rotated in well defined steps registered by an angle encoder to receive information on impact times of the nuclei. Using this time resolving system geomagnetically forbidden particles can be detected. The chemical composition and energy spectra of mainly CNO particles are examined using a rotated 300 microns m thick CR-39 foil beneath a fixed 100 microns m thick Kodak-Cellulose Nitrate foil. About 600 sq cm have been scanned yielding nearly 100 nuclear tracks within an energy range of approximately 8 to 30 MeV/nuc. The calibration is done by means of a postflight irradiation with 410 MeV/nuc Fe-56 at Berkeley Laboratory, California, USA. Relative abundances and energy spectra are presented.

Beaujean, R.↗
DOE OSTI2023

Simulation tools, first results and experimental status of the MURAVES experiment

The MUon RAdiography of VESuvius (MURAVES) project aims at the study of Mt. Vesuvius, an active and hazardous volcano near Naples, Italy, with the use of muons freely and abundantly produced by cosmic rays. In particular, the MURAVES experiment intends to perform muographic imaging of the internal structure of the summit of Mt. Vesuvius. The challenging measurement of the rock density distribution in its summit by muography, in conjunction with data from other geophysical techniques, can help model possible eruption dynamics. The MURAVES apparatus consists of an array of three independent and identical muon trackers, with a total sensitive area of 3 square meters. In each tracker, a sequence of 4 XY tracking planes made of plastic scintillators is complemented by a 60 cm thick lead wall inserted between the two downstream planes to improve rejection of background from low energy muons. The apparatus is currently acquiring data. This paper presents preliminary results from the analysis of the first data samples acquired with trackers pointing towards Mt. Vesuvius, including the first relative measurement of the density projection of two flanks of the volcano at three different altitudes; we also present the workflow of the simulation chain of the MURAVES experiment and its ongoing developments.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1989

Antiprotons in cosmic rays and their implications

A brief description of the experiments carried out so far to measure the energy spectrum of antiprotons is made and the reason for the excitement in this field of research is elucidated. The observed spectrum appears to be different form the other components of cosmic rays. Various physical processes by which antiprotons could be created are summarized. The equilibrium spectrum of antiprotons in the Galaxy, arising from each of these processes, is derived for different propagation models. It is shown that no single model can predict correctly the observed data over the entire energy region. However, the recent data at low energies suggest that the conventional models with large amount of matter traversal by cosmic rays, either in the source region or during propagation, can reproduce the data closely. The implications of these propagation models for other components are discussed and the need for more observations is emphasized.

Stephens, S. A.↗
NASA NTRS1981

Cosmic ray detector for high energy iron nuclei

An experiment to directly measure the differential energy spectra of nuclei with charge between 15-28 inclusive with a balloon borne instrument is presented. A High Energy Gas Cerenkov Spectrometer (HEGCS) is described, and consists of a 3 m diam drum 4.5 m tall containing three light diffusion chambers. A hodoscopic array of scintillators emit light into the top and bottom light chambers which serve for track recordings of the trajectory and charge of incident cosmic rays. A center chamber pressure vessel, the HEGCS, has a 4.0 m sr and a threshold of 50 GeV/amu. The hexagonal array scintillators have 24 elements/array feeding photomultiplier tubes at the vertices between the scintillators, with other PMTs located around the top and bottom chambers to capture escaped scintillator light. The HEGCS is filled with freon-12, with reflective paint on the inner surface to convert UV Cerenkov photons into visible photons near 425 nm.

Streitmatter, R. E.↗
NASA NTRS2003

The EUSO Mission

The Extreme Universe Space Observatory (EUSO) experiment will use the Earth's atmosphere viewed from space as a detector of extreme energy cosmic rays (EECRs). EUSO s collecting power will exceed previous experiments by more than a factor of 10, making it possible to extend the cosmic ray spectrum beyond 100 EeV with high statistics. This will make it possible to investigate in detail the spectrum beyond the point were the Greisen-Zatsepin-Kuzmin effect is expected to strongly attenuate the proton flux and even beyond the energy where cosmic ray nuclei should be photo-disintegrated by interactions with the universal microwave background. EUSO makes its measurements by detecting the extensive air showers (EASs) that result from the interactions of the EECRs. Looking down from its birth on the International Space Station though wide-angle optics, EUSO records a high-speed movie clip of passage of each EAS though the atmosphere with the light from nitrogen fluorescence and Cherenkov light reflected from the EAS landing point. These movie clips are analyzed to determine the EECR arrival direction and energy. The data also allow neutrino-induced EASs to be discriminated from nuclear-induced showers.

Adams, J. H.↗
NASA NTRS2001

Atmospheric Fluorescence Yield

Several existing and planned experiments estimate the energies of ultra-high energy cosmic rays from air showers using the atmospheric fluorescence from these showers. Accurate knowledge of the conversion from atmospheric fluorescence to energy loss by ionizing particles in the atmosphere is key to this technique. In this paper we discuss a small balloon-borne instrument to make the first in situ measurements versus altitude of the atmospheric fluorescence yield. The instrument can also be used in the lab to investigate the dependence of the fluorescence yield in air on temperature, pressure and the concentrations of other gases that present in the atmosphere. The results can be used to explore environmental effects on and improve the accuracy of cosmic ray energy measurements for existing ground-based experiments and future space-based experiments.

Adams, James H., Jr.↗
NASA NTRS1985

Heavy nucleus collisions between 20 and 60 GeV/nucleon

Interest in studying relativistic nucleus-nucleus interations arises from the fact that they offer an opportunity to probe nuclear matter at high density and temperature. It is expected that under such extreme conditions a transition from hadronic matter into quark-gluon plasma occurs and that in the interactions of highly relativistic nuclei such conditions are created. Cosmic rays remain a unique source of high energy heavy nuclei. The Japanese-American Cooperative Emulsion Experiment (JACEE-3) was designed to study the collisions of heavy cosmic ray nuclei with different nuclear targets at energies beyond 20 GeV/nucleon. JACEE-3 experiment was carried out using a combined electronic counters and an emulsion chamber detector, which was exposed to the cosmic rays on a balloon at an altitude of 5 g/sq cm.

Burnett, T. H.↗