Engineering topics

Stone, E. C.

Publications and source records attributed to Stone, E. C..

At least 127 records · Page 7

NASA NTRS1985

Energy spectra of elements with 18 less than or equal to Z less than or equal to 28 between 10 and 300 GeV/amu

The HEAO-3 Heavy Nuclei Experiment is composed of ionization chambers above and below a plastic Cherenkov counter. The energy dependence of the abundances of elements with atomic number, Z, between 18 and 28 were measured at very high energies where they are rare and thus need the large area x time of this experiment. The measurements of the Danish-French HEAO-3 experiment were extended to higher energies, using the relativistic rise of ionization signal as a measure of energy, and determine source abundances for Ar and Ca.

Jones, M. D.↗

NASA NTRS1985

Elemental abundances of cosmic rays with Z33 as measured on HEAO-3

The Heavy Nuclei Experiment on HEAO-3 uses a combination of ion chambers and a Cerenkov counter. During analysis, each particle is assigned two parameters Z sub c and Z sub l proportion signal is double valued, a unique assignment of particle charge, Z, is not possible in general. Previous work was limited to particles of either high rigidity or low energy, for which a unique charge assignment was possible, although those subsets contain less than 50% of the total number of particles observed. The use of the maximum likelihood technique to determine abundances for the complete data set from approximately 1.5 to approximately 80 GeV/amu is studied.

Newport, B. J.↗

NASA NTRS1985

Abundances of secondary elements among the ultra heavy cosmic rays: Results from HEAO-3

Observations of the abundances of elements of charge 62 or = Z or = 73 in the cosmic radiation from the HEAO-3 Heavy Nuclei Experiment (HNE) are discussed. These elements, having solar, and presumably source, abundances much less than the heavier Pt and Pb groups, are expected to be largely products of spallation. Thus they are indicators of the conditions prevailing during the propagation of cosmic rays. The abundances have changed from those reported previously due to a different data selection. This resulted in better charge resolution and in a higher mean energy for the particles. All the particles included in this paper were required to have had a cutoff rigidity R sub c 5 GV. This allowed the charge determination to be based solely on the Cerenkov measurement.

Klarmann, J.↗

NASA NTRS1985

Lead, platinum, and other heavy elements in the primary cosmic radiation: HEAO-3 results ssc wg032961 cb553097

An observation of the abundances of cosmic-ray lead and platinum-group nuclei using data from the HEAO-3 Heavy Nuclei Experiment (HNE) which consisted of ion chambers mounted on both sides of a plastic Cerenkov counter is reported. Further analysis with more stringent selections, inclusion of additional data, and a calibration at the LBL Bevalac, have allowed obtaining the abundance ratio of lead and the platinum group of elements for particles that had a cutoff rigidity R sub c 5 GV.

Waddington, C. J.↗

NASA NTRS1985

Implications of source abundances of ultraheavy cosmic rays

The ratio of cosmic-ray source abundance to solar-system abundance for individual elements is examined. In particular correlations of these ratios with first-ionization potential (FIP) and also with the expected mass-to-charge ratio (A/Q) of the elements in a million-degree plasma are examined. The FIP correlation were previously examined and shown that the correlation is affected by the choice of C2 or C1 chondritic meteorites as the solar-system standard for comparison. An A/Q correlation was suggested by Eichler and Hainebach as a consequence of their model of shock acceleration in the hot interstellar medium, and has been examined by Israel. These correlations are presented.

Binns, W. R.↗

NASA NTRS1985

Interactions of heavy nuclei, Kr, Xe and Ho, in light targets

Over the past few years, the HEAO-3 measurements of the abundance of ultra-heavy cosmic ray nuclei (Z 26) at Earth were analyzed. In order to interpret these abundances in terms of a source composition, allowances must be made for the propagation of the nuclei in the interstellar medium. Vital to any calculation of the propagation is a knowlege of the total and partial interaction cross sections for these heavy nuclei on hydrogen. Until recently, data on such reactions have been scarce. The semi-empirical formalism of Silberberg and Tsao were relied upon to predict the partial cross sections. However, now that relativistic heavy ion beams are available at the LBL Bevalac, some of the cross sections of interest can be measured at energies close to those of the cosmic ray nuclei being observed.

Kertzman, M. P.↗

NASA NTRS1985

The response of ionization chambers to relativistic heavy nuclei

As part of a recent calibration at the LBL Bevalac for the Heavy Nuclei Experiment on HEAO-3, the response of a set of laboratory ionization chambers were compared to beams of 26Fe, 36 Kr, 54Xe, 67 Ho, and 79 Au nuclei at maximum energies ranging from 1666 MeV/amu for Fe to 1049 MeV/amu for Au. The response of these chambers shows a significant deviation from the expected energy dependence, but only a slight deviation from Z squared scaling.

Newport, B. J.↗

NASA NTRS1985

Initial results from the Caltech/DSRI balloon-borne isotope experiment

The Caltech/DSRI balloon-borne High Energy Isotope Spectrometer Telescope (HEIST) was flown successfully from Palestine, Texas on 14 May 1984. The experiment was designed to measure cosmic ray isotopic abundances from neon through iron, with incident particle energies from approximately 1.5 to 2.2 GeV/nucleon, depending on the element. During approximately 38 hours at float altitude, 10 to the 5th events were recorded with Z or = 6 and incident energies 1.5 GeV/nucleon. We present results from the ongoing data analysis associated with both the pre-flight Bevalac calibration and the flight data.

Schindler, S. M.↗

NASA NTRS1985

Measurements of Fe and Ar fragmentation cross sections

Measurements are reported of the yields of individual isotopes of Cr to Co (Z = 24 to 27) resulting from the fragmentation of 56Fe, and the isotopes of Mg to K (Z = 12 to 19) resulting from the fragmentation of 40Ar.

Lau, K. H.↗

NASA NTRS1985

A balloon-borne imaging gamma-ray telescope

A balloon-borne coded-aperture gamma-ray telescope for galactic and extragalactic astronomy observations is described. The instrument, called GRIP (Gamma Ray Imaging Payload), is designed for measurements in the energy range from 30 keV to 5 MeV with an angular resolution of 0.6 deg over a 20 deg field of view. Distinguishing characteristics of the telescope are a rotating hexagonal coded-aperture mask and a thick NaI scintillation camera. Rotating hexagonal coded-apertures and the development of thick scintillation cameras are discussed.

Althouse, W. E.↗

NASA NTRS1985

The energy spectrum of Jovian electrons in interplanetary space

The energy spectrum of electrons with energies approximately 10 to approximately 180 MeV measured with the electron telescope on the Voyager 1 and 2 spacecraft in interplanetary space from 1978 to 1983 is reported. The kinetic energy of electrons is determined by double dE/dx measurements from the first two detectors (D1,D2) of a stack of eight solid state detectors and by the range of particle penetration into the remaining six detectors (D3 to D8) which are interleaved with tungsten absorbers.

Christon, S. P.↗

NASA NTRS1985

Precision measurements of solar energetic particle elemental composition

Using data from the Cosmic Ray Subsystem (CRS) aboard the Voyager 1 and 2 spacecraft, solar energetic particle abundances or upper limits for all elements with 3 = Z = 30 from a combined set of 10 solar flares during the 1977 to 1982 time period were determined. Statistically meaningful abundances have been determined for the first time for several rare elements including P, Cl, K, Ti and Mn, while the precision of the mean abundances for the more abundant elements has been improved by typically a factor of approximately 3 over previously reported values.

Breneman, H.↗

NASA NTRS1985

Solar coronal and photospheric abundances from solar energetic particle measurements

Solar energetic particle (SEP) elemental abundance data from the Cosmic Ray Subsystem (CRS) aboard the Voyager 1 and 2 spacecraft are used to derive unfractionated coronal and photospheric abundances for elements with 3 = or Z or = 30. The ionic charge-to-mass ratio (Q/M) is the principal organizing parameter for the fractionation of SEPs by acceleration and propagation processes and for flare-to-flare variability, making possible a single-parameter Q/M-dependent correction to the average SEP abundances to obtain unfractionated coronal abundances. A further correction based on first ionization potential allows the determination of unfractionated photospheric abundances.

Breneman, H.↗

NASA NTRS1985

Latitude variation of recurrent fluxes in the outer solar system

Recurrent low energy (not less than 0.5 MeV) proton flux enhancements, reliable indicators of corotating plasma inteaction regions in interplanetary space, have been observed on the Voyager 1 and 2 and Pioneer 11 spacecraft in the heliographic latitude range 2 deg S to 23 deg N and the heliocentric radial range 11 to 20 AU. After a period of rather high correlation between fluxes at different latitudes in early 1983, distinct differences develop. The evolution of the fluxes appears to be related to the temporal and latitudinal dynamics of solar coronal holes, suggesting that information about the latitudinal structure of solar wind stream sources propagates to these distances.

Christon, S. P.↗

NASA NTRS1985

Differential measurement of cosmic-ray gradient with respect to interplanetary current sheet

Simultaneous magnetic field and charged particle measurements from the Voyager pacecraft at heliographic latitude separations from 10 deg to 21 deg are used to determine the latitude gradient of the galactic cosmic ray flux with respect to the interplanetary current sheet. By comparing the ratio of cosmic ray flux at Voyager 1 to that at Voyager 2 during periods when both spacecraft are first north and then south of the interplanetary current sheet, we find an estimate of the latitudinal gradient with respect to the current sheet of approximately -0.15 + or- 0.05%/deg under restricted interplanetary conditions.

Christon, S. P.↗

NASA NTRS1985

Changes in the energy spectrum of anomalous oxygen and helium during 1977 - 1985

Data from the cosmic-ray experiment on the Voyager spacecraft was used to assure the energy spectrum of anomalous O and He during the period 1977 to 1985. These spectra change dramatically after the middle of 1980, with the peak or plateau region of the differential spectrum shifting to a higher energy. This change appears to be related to the reversal of the solar magnetic field and could imply that particle drifts are important to the acceleration or propagation of these particles.

Cummings, A. C.↗

NASA NTRS1985

Solar cycle variations of the anomalous cosmic ray component

The intensity of the anomalous cosmic ray component, consisting of He, N, O, and Ne, has long been known to be especially sensitive to the effects of solar modulation. Following its discovery in 1972, this component dominated the quiet-time flux of cosmic ray nuclei below approximately 30 MeV/nucleon during the 1972 to 1978 solar minimum, but then became essentially unobservable at 1 AU with the approach of solar maximum conditions. One recent theoretical model predicts substantial differences in the intensity of the anomalous fluxes from one solar minimum period to the next because of the reversal of the solar magnetic field. Using data from the Caltech experiments on IMP-8 and ICE (ISEE-3), the intensity of anomalous O and He at 1 AU during the years 1972 to 1985 is reported. We hope to determine whether the anomalous fluxes will return to their 1972 to 1978 levels, as predicted by spherically symmetric modulation models, or whether they will fail to return to 1 AU, as suggested by modulation models in which gradient and curvature drifts dominate.

Mewaldt, R. A.↗

NASA NTRS1985

Radial and latitudinal gradients of anomalous oxygen during 1977 - 1985

The radial gradient of anomalous O remained constant during 1977 to 85 at approximately 10 to 15%/AU although the intensity changes by more than a factor of 100. These results can be used to deduce that most of the modulation of the intensities of these particles is occurring beyond 27 AU. Evidence for a latitudinal gradient of approximately +3%/degree at low energies (7.1 to 10.6 MeV/nucl) was also found.

Webber, W. R.↗