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  • 11
    Digitale Medien
    Digitale Medien
    Further evidence for a cosmic ray selection mechanism (1972)
    Springer
    Astrophysics and space science 16 (1972), S. 405-412 
    Details
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A comparison has been made between the overabundance of heavy elements in the primordial cosmic radiation and the cross-section for ionization by charged particle impacts. It is found that there is evidence that this type of ionization is important for the selection of cosmic ray particles.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00642339
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  • 12
    Digitale Medien
    Digitale Medien
    Composition of low energy cosmic radiation from silicon to nickel (1973)
    Springer
    Astrophysics and space science 21 (1973), S. 211-222 
    Details
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The charge composition of the cosmic radiation for the elements withZ≥14 has been studied in a stack of nuclear emulsions exposed at Fort Churchill in July 1967. Particles stopping in the stack have been measured with a nuclear track photometer to determine the charge. Relative abundances are given for the elements silicon to nickel and comparison is made with other investigations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00642200
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  • 13
    Digitale Medien
    Digitale Medien
    The composition of low energy primaries withZ≥9 in cosmic radiation (1970)
    Springer
    Astrophysics and space science 8 (1970), S. 74-85 
    Details
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Photometric mean track width measurements have been made on 81 primary particles (Z≥9) stopping in a nuclear emulsion stack exposed at 2.7 g/cm2 of residual atmosphere at Fort Churchill, Canada. The standard deviation of the charge determinations amounts to 0.14 units of charge for oxygen and increases to 0.40 units for iron nuclei when 10 mm track is measured. The relative abundances of the nuclei in the charge interval 8≤Z≤14 are given for the energy interval 250–400 MeV/nucleon, and comparisons are performed with the results of other measurements. The VH-particles are dominated by iron. The distribution of the VH-particles seems to be consistent with the assumption that the VH-nuclei have in the mean passed through only 1.6±0.5 g/cm2 interstellar matter.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00651657
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  • 14
    Digitale Medien
    Digitale Medien
    The composition of the cosmic radiation and the atomic properties of the elements (1974)
    Springer
    Astrophysics and space science 30 (1974), S. 417-431 
    Details
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The composition of the primordial cosmic radiation has been compared with the solar system composition and that of interstellar matter. It is found that the overabundance of an element in the radiation is approximately proportional to the cross-section for the ionization of neutral atoms of that element through fast charged particle impacts. The results strongly support the assumption that the selection of cosmic ray particles is governed by the atomic properties of the elements.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00648287
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  • 15
    Digitale Medien
    Digitale Medien
    A possible mechanism for the injection of particles into a cosmic ray acceleration region (1971)
    Springer
    Astrophysics and space science 14 (1971), S. 485-500 
    Details
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The composition of the nucleonic component of the primary cosmic radiation has been compared with the natural abundance of the elements. A normalized quotient between the abundance of an element in the radiation and in nature was found to be approximately equal toZ α, whereZ is the atomic number and α is a constant approximately equal to one. The observed excess of the heavy elements can be expected in the radiation if the selection of the cosmic ray particles is performed by ionization through fast electron or proton impacts on neutral matter having ‘normal’ composition. Such a selection mechanism may act in regions in space where fast moving thin plasma clouds collide with clouds of neutral matter. A source model in which the plasma clouds originate in Type II supernova explosions is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00653337
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  • 16
    Digitale Medien
    Digitale Medien
    Isotopic composition of primary cosmic-ray nitrogen and oxygen with consequences for source models (1979)
    Springer
    Astrophysics and space science 63 (1979), S. 215-236 
    Details
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract An experimental investigation of the isotopic composition of cosmic-ray nitrogen and oxygen is reported. The detector is a stack of nuclear emulsions exposed at about 3 g cm−2 atmospheric depth. The mass determinations are based on photometric track width measurements on stopping nuclei. The standard deviation of the mass measurements is 0.46 AMU for nitrogen and 0.50 AMU for oxygen. The energy of the measured nuclei falls in the interval 220–450 MeV nucleon−1 at the top of the atmosphere. The measured isotopic quotients have been extrapolated to near interstellar space with standard methods. The extrapolated quotients are15N/N=0.34±0.10,17O/O=0.02±0.03,18O/O=0.07±0.03. The nitrogen quotient extrapolated to the cosmic-ray source shows that the nitrogenoxygen abundance ratio is approximately the same in the source as in the solar system. The result has been compared with different hypotheses about the source composition and is found to be in best agreement with a hypothesis which states that source matter has approximately the composition of the solar system and that a selection mechanism, which depends on the atomic properties of the elements, is working in the source.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00647759
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  • 17
    Digitale Medien
    Digitale Medien
    The relative abundance of the carbon isotopes12C and13C in primary cosmic radiation (1970)
    Springer
    Astrophysics and space science 7 (1970), S. 231-251 
    Details
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Mass measurements have been performed on stopping cosmic ray carbon nuclei in a nuclear emulsion stack, which was exposed to the primary radiation in a high altitude balloon flight. The mass determinations are based on measurements of mean track width and residual range in the range intervals 0〈R〈0.75 mm and 1〈R〈12 mm. The mean track width measurements have been performed with nuclear track photometers of special construction. The mass measurements in the interval 0〈R〈0.75 mm have given a nearly symmetrical mass distribution. The width of the distribution is equal to that expected for a distribution which contains only one isotope. The result indicates that one of the stable isotopes is appreciably more abundant than the other. The measurements in the range interval 1〈R〈12 mm gave the isotopic ratio13C/12C+13C)=0.08. The ratio has been extrapolated to the cosmic ray source. It is found to be smaller in the source than at the point of measurement. Different assumptions about the origin of the cosmic radiation are discussed with regard to the results obtained in this investigation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00653610
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  • 18
    Digitale Medien
    Digitale Medien
    The cosmic ray boron and carbon isotopic composition measured in nuclear emulsions (1979)
    Springer
    The European physical journal 291 (1979), S. 383-390 
    Details
    ISSN: 1434-601X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A study is made of the isotopic composition of primary cosmic ray boron and carbon in the energy interval 135–390 MeV/n. The quotients11B/(10B +11B) = 0.61 ±0.12 and13C/(12C +13C) = 0.06 ±0.04, valid at the top of the atmosphere, are obtained from photometric measurements on tracks found in an Ilford G5 emulsion stack exposed to the radiation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01408389
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