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Annihilation Lifetime Spectroscopy Using Positrons from Bremsstrahlung Production
Defect and Diffusion Forum, 2012A new type of a positron annihilation lifetime spectroscopy (PALS) system has been set up at the superconducting electron accelerator ELBE [ at Helmholtz-Zentrum Dresden-Rossendorf. In contrast to existing source-based PALS systems, the approach described here makes use of an intense photon beam from electron bremsstrahlung which converts through pair ...
Wagner, A. +6 more
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Mechanical Stability of Porous Copolymers by Positron Annihilation Lifetime Spectroscopy
The Journal of Physical Chemistry C, 2015<p>A set of porous copolymer samples (VP-TRIM, VP-DVB, and VP-DMN) under mechanical stress up to 1.3 GPa was studied in situ using positron annihilation lifetime spectroscopy. A few stages of porosity evolution dissimilar in changes of the pore size distribution (PSD) were observed.
Radosław Tomasz Zaleski +2 more
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Nanovoids in Glasses and Polymers Probed by Positron Annihilation Lifetime Spectroscopy
2011Nanovoids in As2S3-based glasses (As 2S3, (As2S3)85Ag 15, and (As2S3)85(AgI) 15), a polymer and a As2S3-polymer nanocomposite were studied using the positron annihilation lifetime spectroscopy (PALS) technique. After computer treatment of the PALS data recorded, it was found that only two components τ 1 (short-lived) near 0.2 ns and τ 2 (long-lived ...
Kavetskyy T. +5 more
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Investigation of SPPO Membranes by Positron Annihilation Lifetime Spectroscopy
Plasma Science and Technology, 2006Positron annihilation lifetime spectroscopy (PALS) is a powerful technique to study the free volume in polymers. The lifetime of ortho-positronium (o-Ps), a bound state of an electron and a positron, can be used to assess the pore size while the intensity can be used to characterize the number of pores. On the basis of the values of the long-lived o-Ps
Htwe Htwe Yin +3 more
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On the characterization of glassy polymers by positron annihilation lifetime spectroscopy
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1991Abstract The present paper reviews some of our recent results exemplifying the use of positron annihilation lifetime spectroscopy in evaluating the effects of thermal history on the physical properties of glassy polymers. Specifically, studies on thermal cycling, physical aging and structural relaxation in polycarbonate are discussed.
Kenneth J. Heater, Phillip L. Jones
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Design of a slow pulsed positron beam for positron annihilation lifetime spectroscopy
2007 IEEE Nuclear Science Symposium Conference Record, 2007Positron annihilation spectroscopy provides a useful tool for the non-destructive study of subsurface microscopic defects. Variations in the electronic environment, from that of the bulk of the material, caused by defects introduce Coulombic forces which cause positrons to localize at the site of defects. This lifetime can vary from nanoseconds, if the
Alfred G. Hathaway +3 more
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Acidity Effects in Positron Annihilation Lifetime Spectroscopy of Zeolites
The Journal of Physical Chemistry C, 2018Positron annihilation lifetime spectroscopy (PALS) is a tool used to study pore networks in zeolites, as the diffusion of metastable ortho-positronium (o-Ps, an electron–positron bound pair) provides insights into connectivity that cannot be obtained by other techniques.
Robbie Warringham +6 more
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Development of an Electron-Positron Source for Positron Annihilation Lifetime Spectroscopy
2007Abstract : The extremely strong fields produced by focusing powerful laser pulses into minute volumes of material enable relativistic effects to be used to generate radiation, to accelerate particles, and to produce electrons and positrons from vacuum.
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Nanocrystalline alloys studied by positron annihilation lifetime spectroscopy
physica status solidi c, 2007AbstractNanocrystalline alloys present a new class of materials that exhibit interesting magnetic properties. These stem primarily from the presence of crystalline grains with the size of several tens of nanometers embedded in a residual amorphous matrix.
Martin Petriska +4 more
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Study of Chemical Carcinogens by Positron Annihilation Lifetime Spectroscopy
Journal of Applied Spectroscopy, 2013We have used positron annihilation lifetime spectroscopy to study the carcinogens C21H20BrN3, C4H7Cl2O4P, CCl4, CHCl3, AlF3, C8H12N4O, C6H4Cl2 and the non-carcinogens H2O, AlCl3, CH2Cl2, C2H6OS. We have established a correlation between the annihilation characteristics of the studied compounds and their degree of carcinogenicity.
A. A. Pivtsaev +2 more
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