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The first measurements of the fluence of solar particles with nuclear charges not less than 32 and 44 are presented, along with the enhancement factors found. Using a track-etching technique, these transiron nuclei were detected in a window from the Apollo 16 command module which was exposed outside the magnetosphere during the solar-particle event of Apr. 18, 1972.
Delta electrons in nuclear emulsions used in determining nature and energy of cosmic ray particles
Numerical integration of meson-nucleon cascade equations for accelerator shielding calculations
Cosmic ray and nuclear charged particle printout within transparent silver chloride crystals
Literature survey of radiochemical cross sections below 425 MeV
Cosmic ray flux of Z particles from nuclear photographic emulsions during balloon flight
Fabrication of cermets of uranium nitride and tungsten or molybdenum from mixed powders and from coated particles for nuclear fuel elements
Matter accreted on the surfaces of neutron stars consists of energetic particles of a few tens to a couple hundred MeV/nucleon, depending on the neutron star mass. In addition to heat, such particles produce nuclear reactions with the surface material. It is proposed that the recently observed 473 + or - 30 keV spectral feature from the galactic center is gravitationally red-shifted positron annihilation radiation produced at the surfaces of old neutron stars. The principal observational tests of the model would be the detection of nuclear gamma ray lines from the galactic center and red-shifted positron annihilation radiation from the galactic disk.
Energy distribution of high energy electrons as they slow down and thermalize in a gaseous medium is studied. The energy distribution in the entire energy range from source energies down is studied analytically. A helium medium in which primary electrons are created by the passage of heavy-charged particles from nuclear reactions is emphasized. A radiation-induced plasma is of interest in a variety of applications, such as radiation pumped lasers and gaseous core nuclear reactors.
Matter accreted on the surfaces of neutron stars consists of energetic particles of a few tens to one or two hundred MeV per nucleon, depending on the neutron-star mass. In addition to heat, such particles produce nuclear reactions with the surface material. It is proposed that the recently observed 473 plus or minus 30 keV spectral feature from the galactic center is gravitationally redshifted positron-annihilation radiation produced at the surfaces of neutron stars. The principal observational tests of the model would be the detection of nuclear gamma-ray lines from the galactic center.
Sedimentary barites from South Africa and Western Australia (about 3 billion years old) contain spallogenic Xe isotopes produced by reactions of Ba with nuclear-active particles in cosmic rays. 'Surface residence time' of these samples was calculated from the observed concentrations of spallogenic Xe-126. Comparison of spallogenic ratios of Xe-131/Xe-126 in the two samples provides evidence for the reaction Ba-130(n, gamma) yields Xe-131, which is characterized by a large number of resonances for neutron absorption in the epithermal region. This observation lends additional support to the conclusions already reached regarding the origin of anomalous Xe-131 in lunar samples.
The ISEE-1 and ISEE-C instruments are designed to measure the elemental abundances, charge state composition, energy spectra, and angular distributions of energetic ions in the energy range 2 keV/charge to 80 MeV/nucleon and electrons between 75 and 1300 keV. The instrument consists of three sensor systems: (1) ULECA which is an electrostatic deflection system with rectangular solid-state detectors for the 3-560 keV/charge range; (2) ULEWATT which is a double dE/dX vs E thin-window flowthrough proportional counter/solid-state detector telescope for the 0.2-80 MeV/nucleon (Fe) range; and (3) ULEZEQ which is a combination of an electrostatic deflection analyzer and a thin-window dE/dX vs E system with thin-window proportional counter and position-sensitive solid-state detector. The applications of the instruments to solar and interplanetary phenomena and to magnetospheric acceleration and trapped particles are discussed.
A description is provided of the medium energy cosmic ray experiment on board the ISEE-C spacecraft. This experiment is designed to measure the charge composition of nuclear energetic particles over wide ranges in energy (1-500 MeV/nucleon) and in charge (Z equals 1-28). Individual isotopes are resolvable for Z equals 1-7 over a restricted energy range. Electrons of 2-10 MeV are measured as well. These measurements are accomplished using all solid-state detector telescopes with detectors ranging in thickness from 15-3000 microns. The scientific goals of the experiment are also described. These include study of the composition of energetic particles from the sun and from the galaxy, the acceleration and flow of particles in the interplanetary medium, and electrons from Jupiter. Heliospheric gradients and other characteristics of solar modulation will be measured in conjunction with identical telescopes flown on the Voyager 1 and 2 spacecraft and similar telescopes on Pioneer 10 and 11.
Charged particle-induced nuclear reactions were used in the following problems: the determination of elemental abundances of boron and fluorine in carbonaceous chondritic meteorites; the identification of products of lunar vulcanism; and the study of solar wind-implanted atoms in lunar materials. The technique was seen as an important supplement to other methods of elemental and isotopic analysis. This was especially true for cases involving light elements at very low concentrations or where high resolution depth distribution information was needed in non-destructive analysis.
A generalized optical model heavy ion reaction theory is extended to include correlation effects between projectile and target constituents according to the Pauli exclusion principle. These correlation effects are significant for accurately predicting cross sections for projectile nucleus abrasions, but are relatively unimportant for determining total and absorption cross sections for heavy ion collisions. For lighter nuclei, predictive capabilities were also improved by developing an analytic method for extracting their nuclear single particle density distributions from experimentally measured harmonic well charge density distributions. This improved theory is compared with previous theoretical predictions and recent experimental results.
The Second International Workshop on Harmonic Oscillators was held at the Hotel Hacienda Cocoyoc from March 23 to 25, 1994. The Workshop gathered 67 participants; there were 10 invited lecturers, 30 plenary oral presentations, 15 posters, and plenty of discussion divided into the five sessions of this volume. The Organizing Committee was asked by the chairman of several Mexican funding agencies what exactly was meant by harmonic oscillators, and for what purpose the new research could be useful. Harmonic oscillators - as we explained - is a code name for a family of mathematical models based on the theory of Lie algebras and groups, with applications in a growing range of physical theories and technologies: molecular, atomic, nuclear and particle physics; quantum optics and communication theory.
In ways similar to experiments in nuclear and particle physics, high-energy astrophysics usesgamma rays and energetic charged particles toprobe processes that involve large energy transfers.Since its launch in 2008, the international Fermi Gamma-Ray Space Telescope has been exploringnatural particle accelerators and the interactionsof high-energy particles in the universe. Withsources ranging from thunderstorms on Earth to galaxies and exploding stars in distant parts of the cosmos, the telescopes subjects of study are almostas diverse as were those of the scientist whose name it bears.