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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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Least squares representation of inelastic cross sections and particle emission spectra from nucleon-nucleus collisions
Summary of studies on Monte Carlo method for nucleon transport through dense matter
Nucleon isobars and hyperons carrying off interstellar and intergalactic proton-proton collision energy, discussing high energy gamma ray decay product
Liquid and slush hydrogen density data measured by fast response nucleonic densitometer, reviewing liquid-vapor quality data obtained from cryogenic meter
Optimal configuration for zero-g nucleonic fuel gage
Computer programs to calculate and analyze pion and nucleon interaction within prescribed medium referred to as PROPER 3C Transport Code
Charged scalar static model, using dispersion theory to include two-meson effects in two nucleons binding energy at zero separation
The exact nucleon-deuteron elastic single scattering integral was calculated numerically in order to evaluate errors in sticking factor approximations. A similar analysis made by using S wave separable potentials concluded that errors for these approximations were negligible except near backward angles where they were found to be about 10 percent.
An experiment has been carried out at the bevatron on the nuclear fragmentation of nitrogen-14 ions at an energy of 2.1 billion electron volts (Gev) per nucleon. Because of the near equality of the velocities of the nitrogen-14 beam and the fragmentation products at an angle of 0 deg, we find it possible to identify the nuclear fragments isotopically.
Calculation of nonelastic interactions corresponding to continuum-state transitions using the intranuclear-cascade evaporation approach. Spallation yields, energy- and angle-dependent spectra, particle multiplicities, and nonelastic cross sections are calculated for incident nucleons and pi mesons with energies below 3 GeV on complex nuclei. Comparisons with experimental data are made, and, in general, the agreement is good. Discrepancies in these comparisons are discussed with respect to the deficiencies in the model.
Sloan's conclusion (1969) that terms of the multiple-scattering series beyond single scattering contribute only to S- and P-wave amplitudes in an S-wave separable model is examined. A comparison of experiments with the calculation at 146 MeV shows that the conclusion is valid in nucleon-deuteron scattering applications.
Approximate solutions of the coupled-channel equations for high-energy composite particle scattering are obtained and are applied to the nuclear scattering problem. Relationships between several approximation procedures are established and discussed. The eikonal formalism is used with a small-angle approximation to calculate the coherent elastic scattered amplitude from which total and absorption cross sections are derived. Detailed comparisons with nucleon-nucleus experiments show agreement within 5 percent except at lower energies where the eikonal approximation is of questionable accuracy. Even at these lower energies, agreement is within 15 percent. Tables of cross sections required for cosmic heavy-ion transport and shielding studies are presented.
Corotating proton and electron streams are the dominant type of low-energy (i.e., 0.1-10 MeV per nucleon) particle event observed at 1 AU. The radial dependence of these events has been studied between 1 and 4 AU using essentially identical low-energy detector systems on IMP-7, Pioneer-10, and Pioneer-11. It had been expected that at a given energy, the intensity of these streams would decrease rapidly with heliocentric distance due to the effects of interplanetary adiabatic deceleration. Instead, it is observed that from event to event, the intensity either remains roughly constant or increases significantly (more than an order of magnitude) between 1 and 4 AU. It appears that interplanetary acceleration processes are the most plausible explanation. Several possible acceleration models are discussed.
Observations of the low energy quiet-time interplanetary nucleon spectrum obtained by Explorer 47 are examined for March 9-12, 1973, the quietest period from Sept. 26, 1972 through Feb. 15, 1975. The quiet-time energy spectrum may be represented by a power law with an index of about -3.1. The H/He ratio below 2 MeV is about 10. The ratio of antisunward to sunward intensities is about 2.6, increasing to about 8.55 in a frame moving with the solar wind. The angular distributions show that in the 0.3-0.5 MeV range most of the proton intensity originates in the earth's magnetosphere. The spectral behavior and enhancement of proton counting rates during microbursts suggest that the magnetosphere is a significant source at energies up to 2 MeV. The observed intensities are lower than those reported by Simpson and Tuzzolino (1973) by factors of 3 to 10. It is suggested that the low energy upturn in the quiet-time interplanetary proton spectrum may be related to particle emissions from planetary magnetospheres, such as that of Jupiter.
The paper presents a model of high-energy hadron-hadron scattering where each hadron is a fully absorbing scatterer with a radius that increases with energy. The energy dependence of the radius is chosen such that the total cross section has the energy behavior of the Froissart bound (which means that the cross sections are rising to infinity). The model is used to obtain amplitudes for pion-nucleon scattering.
To investigate the relationship between solar activity and cosmic-ray modulation, time series of the nucleonic flux and of solar plages, sunspots, centimeter radio noise, and the brightness of the white-light corona at 1.1 and 1.5 solar radii from the center of sun are cross-correlated. Data pertain to the years 1964-1967 during the ascending phase of the current solar cycle. The amplitudes and phases of correlation functions for filtered and unfiltered indices are discussed. The existence of a superior solar index for relating solar activity to long-term modulation is not yet demonstrated conclusively, and the time lag of modulation is too poorly determined to permit its use in estimating the radius of the modulation region.
A description is given of an experiment which was designed to measure the spectra and composition of cosmic-ray hydrogen and helium isotopes in the interval 120-280 MeV per nucleon to compare with the recent values observed at low energies and also with the only earlier measurement in this high-energy regime. The results presented were obtained during a high-altitude balloon flight from Thompson, Manitoba, in 1973 August. This flight occurred during the period in which the presence of the anomalous component in the helium spectrum became apparent, and provides the opportunity of determining whether this component extends to higher energies than those studied by satellite experiments. The results place an upper limit on the flux of 'anomalous' He-4 (which appeared at low energy in 1972) of at most 15% in the energy range of this experiment, and combined with the low-energy observations of the Chicago group, show an energy dependence of the average ratio of the helium isotopes in the modulated cosmic rays which is difficult to reconcile with current modulation models.
Utilizing an optical model potential approximation to the exact nucleus-nucleus multiple-scattering series, optical potentials for nucleon-nucleus and nucleus-nucleus collisions are analytically derived. These expressions are applicable to light and medium cosmic ray nuclei as their single-particle density distributions are analytically determined, without approximation, from their actual harmonic well charge density distributions. Pauli correlation effects are included through the use of a simple Gaussian function to replace the usual expression obtained in the infinite nuclear matter approximation.