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  • 1
    Electronic Resource
    Electronic Resource
    The mean lifetime of orthopositronium in vacuum (1977)
    [s.l.] : Nature Publishing Group
    Nature 269 (1977), S. 109-112 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Various measurements and calculations of the vacuum lifetime of ortho-positronium have given widely divergent values. There are indications that these differences are now gradually being ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/269109a0
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Measurement of positron-rare gas total cross-sections at intermediate energies (1976)
    Springer
    Applied physics 11 (1976), S. 321-325 
    Details
    ISSN: 1432-0630
    Keywords: 78.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Total scattering cross-sections for positrons in the rare gases in the energy range of 2–960 eV have been measured using a time-of-flight system for which the uncertainty arising from forward scattering is substantially lower than in the 1974 experiment of Canter et al. A comparison of these cross-sections with current theoretical estimates is made.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00919360
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  • 3
    Electronic Resource
    Electronic Resource
    Total cross-sections for the scattering of positrons by helium, neon, and argon at intermediate energies (1979)
    Springer
    Applied physics 19 (1979), S. 431-437 
    Details
    ISSN: 1432-0630
    Keywords: 34 ; 78.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A slow positron beam time of flight system in which scattering is localised to a region of the flight path close to the slow positron source is described. Total cross-sections measured in helium, neon, and argon at intermediate energies are presented. The results for helium and neon are in agreement with the recent results of Brenton et al. While significant disagreement still exists in the argon data. The helium and neon data are in agreement with the sum rule predictions of Bransden et al.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00930108
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    The analysis of data obtained with time to amplitude converter and multichannel analyser systems (1974)
    Springer
    Applied physics 5 (1974), S. 223-230 
    Details
    ISSN: 1432-0630
    Keywords: Positron annihilation ; Analysis of t.a.c.-m.c.a. data
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract An exact general formula is derived relating the data obtained from t.a.c-m.c.a. systems to the input signal distribution; it is shown how the latter is modified by the measuring process. A general method of data correction is given, together with important approximations, which evaluates the input signal distribution from the data without any loss of signal. A simple and accurate method of system calibration based only on counting and not requiring the use of calibrated delay lines is also given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00928133
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  • 5
    Electronic Resource
    Electronic Resource
    A field-assisted moderator for low-energy positron beams (1987)
    Springer
    Applied physics 42 (1987), S. 111-116 
    Details
    ISSN: 1432-0630
    Keywords: 78.70 ; 72.90 ; 79.90
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A new positron field-assisted (FA) moderator based on the drift of positrons across a cooled silicon crystal is proposed. Using estimates for both theβ + implantation profile and attainable drift velocities, the efficiency of drift to a slow e+ emitting surface is calculated using a diffusion equation which incorporates terms describing positron drift and annihilation. It is conjectured that efficiencies of up to 10% can be achieved. The use of epitaxially grown metallic suicide contacts to facilitate the application of the electric field is described and the consequences of using such contacts are fully discussed. Applications of the FA transmission mode moderator described here to produce timed brightness enhanced beams are briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00616719
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  • 6
    Electronic Resource
    Electronic Resource
    Measurement of total scattering cross-sections for positrons of energies 2–400 eV on molecular gases: H2, D2, N2, CO (1974)
    Springer
    Applied physics 4 (1974), S. 89-90 
    Details
    ISSN: 1432-0630
    Keywords: Positron-molecular gas cross-sections ; Cross-section measurements:e +-molecular gases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The results of a time-of-flight experiment are presented, in which the total cross-sections for 2–400 eV positrons on H2, D2, N2, and CO were measured.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00884160
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  • 7
    Electronic Resource
    Electronic Resource
    Total cross-section measurements for 2–400 eV positrons in the rare gases (1974)
    Springer
    Applied physics 3 (1974), S. 249-249 
    Details
    ISSN: 1432-0630
    Keywords: Positron-rare gas cross-sections ; Cross-section measurements:e +-rare gases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Experimentally determined values of the total scattering cross-sections for positrons in the energy range 2–400 eV on He, Ne, Ar, Kr and Xe are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00884506
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    Paper (German National Licenses)
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  • 8
    Electronic Resource
    Electronic Resource
    A simple positron lifetime system suitable for low density gases (1974)
    Springer
    Applied physics 3 (1974), S. 271-273 
    Details
    ISSN: 1432-0630
    Keywords: Positron annihilation ; Positron lifetimes in gases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A conventional positron lifetime system is described which gives data of high statistical accuracy and is especially suitable for gases at low density. Several factors contribute to the significant improvement in performance. The fraction of positrons annihilating in the gas is greatly enhanced by backscattering, and the small dimensions of the pressure vessel coupled with large plastic scintillators yields about 1200 coincidence events per second. Simple electronics are used with no side channel gating, and very clean spectra are obtained with overall resolution better than 1.5 nsec. The true start and stop pulses are counted, which enables the data to be treated by the authors' signal restoration method. The results of measurements in Ar−CO mixtures and data for H2 and D2 are presented and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00887274
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  • 9
    Electronic Resource
    Electronic Resource
    Early experiments with slow positrons in atomic physics (1994)
    Springer
    Hyperfine interactions 89 (1994), S. 3-17 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The major steps in the evolution of techniques for producing positron beams of well defined energies over the last 25 years are reviewed. Developments in the methods of using these beams for experiments in atomic physics are then traced historically
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02064492
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