A new proton fluence model for E greater than 10 MeV

Researchers describe a new engineering model for the fluence of protons with energies greater than 10 MeV. The data set used is a combination of observations made primarily from the Earth's surface between 1956 and 1963 and observations made from spacecraft in the vicinity of Earth between 1963 and 1985. With this data set we find that the distinction between ordinary proton events and anomalously large proton events made in earlier work disappears. The greater than 10 MeV fluences at 1 AU calculated with the new model are about twice those expected on the basis of models now in use. In contrast to earlier models, results do not depend critically on the fluence from any one event

Nikolai Polissky: the phenomenon of the individual and collective in the author’s creative project

The article is devoted to the problem of comparing the individual creative path of the artist and his activities within the art group. This problem is considered on the example of the work of the contemporary artist N. V. Polissky, who for some time was part of the group “Mitki”, after leaving which he began an individual creative path.Статья посвящена проблеме сопоставления индивидуального творческого пути художника и его деятельности внутри арт-группы. Данная проблема рассматривается на примере творчества современного художника Н. В. Полисского, некоторое время входившего в состав группы «Митьки», покинув которую он начал индивидуальный творческий путь

The isotopic composition of cosmic-ray B, C, N, and O: Evidence for an overabundance of ^(18)O

New observations of galactic cosmic rays at higher energies (~400-780 MeV nucleon^(-1)) than obtained in previous direct mass measurements have resulted in determinations of the isotopic composition of B, C, N, and O. The derived cosmic-ray source abundances provide evidence for an enhancement of ^(18)O/^(16)O by a factor of 5.6 ± 1.9 over the solar system value and give a ^(13)C/^(12)C ratio consistent with the solar system abundance ratio, but lower than some recent measurements of the local interstellar medium

Response of Ionization Chambers and Cherenkov Counters to Relativistic Ultraheavy Nuclei

We shall report results from a calibration of a set of high-resolution ionization chambers and Cherenkov counters at the Lawrence Berkeley Laboratory Bevalac, in November 1986. We obtained exposures to beams of 26Fe, 57La, 67Ho, and 79Au, at several diffyfent energies, ranging from -300 MeV/amu to a maximum between 1 and 1.6 Ge V lamu. The detectors were basically similar to those used in the HEA0-3 HNE (Binns et al. 1981) and these exposures were intended to calibrate the response of the HNE detectors to UH nuclei in the cosmic radiation. For nuclei of low .atomic number (Z), the response of these detectors scales like Z2; however, at high Z this scaling is expected to break down (Ahlen 1980,1982; Derrickson et til. 1981)

Anisotropy of Galactic Iron of Energy 30 to 500 GeV/amu Studied by HEAO-3

The anisotropy of cosmic ray iron observed by the Heavy Nuclei Experiment [1] on the HEA0-3 spacecraft has been studied. A high rigidity data set was chosen by requiring the Stoermer cutoff be greater than 7 GV, and the energy of individual events was determined by relativistic rise in the ion chamber signal [2]. Events which have estimated rigidity well above their Stoermer cutoff rigidity were chosen in order to reduce the effect of the geomagnetic field on the cosmic ray trajectories. Selecting events with estimated rigidity greater than ~58 GV from eight months of data yields 2459 events. This data set allows an anisotropy measurement with a statistical uncertainty of 3%. We will continue to try increasing the size. of the selected data set while limiting systematic errors due to the geomagnetic and interplanetary fields

The Abundances of Ultraheavy Elements in the Cosmic Radiation

Analysis of a new, higher resolution data set from the Heavy Nuclei Experiment on the HEA0-3 spacecraft has yielded the cosmic ray abundances relative to iron of oddeven element pairs with atomic number, Z, in the range 33≤Z≤60. The abundances are consistent with a solar-system source provided an allowance is made for a source fraetionation based on first ionization potential (FIP). However, extending this analysis· to element groups with Z>60, we find enhancements of the Pt group (74≤Z≤80) abundance relative to the solar system and a corresponding increase in the largely secondary nuclei in the range 62≤Z≤73, in agreement with recent Ariel-6 results. These abundances suggest an enhancement of the r-process contribution to the source of the Z > 60 nuclei

The Isotopic Composition of Cosmic Ray B, C, N, and O: Evidence for an Overabundance ^(18)O

New observations of galactic cosmic rays at higher energies (about 400-780 MeV nucleon^(-1)) than obtained in previous direct mass measurements have resulted in determinations of the isotopic composition of B, C, N, and O. The derived cosmic-ray source abundances provide evidence for an enhancement of ^(18)O/^(16)O by a factor of 5.6 ± 1.9 over the solar system value and give a ^(13)C/^(12)C ratio consistent with the solar system abundance ratio, but lower than some recent measurements of the local interstellar medium

Abundances of ultraheavy elements in the cosmic radiation: results from HEAO 3

We report here an analysis 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, 33 ≤Z ≤60, the analysis yields abundances of odd-even element pairs. These 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 > 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 74 ≤ Z ≤ 80, relative to that in a propagated solar system source, and a corresponding increase in the abundance of the largely secondary elements in the range 62 ≤ Z ≤ 73. These abundances suggest that there is an enhancement of the r-process contribution to the source nuclei in the Z > 60 charge region. Over the entire region of charge, standard leaky box models of propagation satisfactorily model secondary production

Isotopic composition of galactic cosmic ray boron, carbon, nitrogen, and oxygen

Relative abundances of the isotopes of galactic cosmic ray B, C, N, and O nuclei have been measured using the balloon-borne High Energy Isotope Spectrometer Telescope (HEIST). Analysis of data collected during the 1988 HEIST flight from Prince Albert, Saskatchewan, has resulted in mass histograms containing ~890 boron, ~3100 carbon, ~910 nitrogen, and ~3300 oxygen nuclei. Masses were derived using both the Cerenkov-Energy and ΔE-E' techniques, achieving a resulting rms mass resolution of ~0.26 amu. These isotopic composition measurements correspond to energy intervals at the top of the atmosphere of ~400-650 MeV/nucleon for boron, 430-670 MeV/nucleon for carbon, 440-680 MeV/nucleon for nitrogen, and 450-780 MeV/nucleon for oxygen, higher than previous direct isotope measurements for these elements. The abundance ratios of carbon, nitrogen, and oxygen at the top of the atmosphere have been interpreted using an interstellar propagation model that includes improved fragmentation cross sections. Because cosmic ray boron is used as a "secondary tracer," the calculated isotope ratios of interest are insensitive to the value chosen for the solar modulation parameter, ø. The resulting abundance ratios for cosmic ray source material include ^(14)N/O = 0.042 ± 0.014 and ^(15)N/O ≤ 0.040, favoring no ^(15)N at the source. The carbon and oxygen isotopes at the cosmic ray source are ^(13)C/^(12)C = 0.005 ± .011 and ^(18)O/^(16)O = 0.0115 ± .0038, compared to solar system values of ^(13)C/^(12)C = 0.011 and ^(18)O/^(16)O = 0.0020. The derived cosmic ray source abundances show a possible enhancement of ^(18)O/^(16)O over the solar system value and a ^(13)C/^(12)C ratio consistent with solar system material. Taking a weighted average of our result with previous high resolution measurements of oxygen results in ^(18)O/^(16)O = 0.0075 ± 0.0024, an enhancement in ^(18)O of 3.75 times the solar system value. Current isotope results are compared with models of cosmic ray origin. Both the supermetallicity model and the "anomalous" solar system model predict an ^(18)O excess in cosmic rays, however, the "anomalous" solar system model also predicts an excess in ^(13)C. The Wolf-Rayet model fits many of the currently observed isotopic excesses in cosmic rays, but the predictions for ^(18)O/^(16)O and the elemental N/O ratio are still in question. We conclude that although further refinements in the Wolf-Rayet model may explain ^(18)O and N/O, none of the presently available models account quantitatively for all of the observed differences in composition between cosmic rays and solar system material.</p

An Analysis Of Factors Associated With Work-leisure Attitudes And Perceptions Of Three Groups Of Women.

PhDAcademic guidance counselingUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/190508/2/7415728.pd