Positron-Annihilation Lifetime Spectroscopy using Electron Bremsstrahlung

11th International Workshop on Positron and Positronium Chemistry

物理学;化学

Wagner, A.^1 ; Anwand, W.^1 ; Butterling, M.^1 ; Cowan, T.E.^1,2 ; Fiedler, F.^1 ; Fritz, F.^1,2 ; Kempe, M.^1,2 ; Krause-Rehberg, R.^3

Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstr. 400, Dresden

01328, Germany^1

Technische Universität Dresden, Dresden

01062, Germany^2

Martin-Luther-Universität Halle-Wittenberg, Institute of Physics, Halle

06099, Germany^3

关键词: Annihilation photons;    Energetic electron;    High-time resolution;    Materials research;    Positron annihilation lifetime spectroscopy;    Pulsed-mode operation;    Single components;    Tomographic reconstruction;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/618/1/012042/pdf
DOI  :  10.1088/1742-6596/618/1/012042

来源: IOP

【 摘 要 】

A new type of an intense source of positrons for materials research has been set up at the superconducting electron linear. The source employs hard X-rays from electron-bremsstrahlung production generating energetic electron-positron pairs inside the sample under investigation. CW-operation allows performing experiments with significantly reduced pile-up artefacts in the detectors compared to pulsed mode operation in conventional accelerators. The high-resolution timing of the accelerator with bunch lengths below 10 ps full width at half maximum (FWHM) allows positron annihilation lifetime spectroscopy (PALS) measurements with high time resolution. A single-component annihilation lifetime of Kaptonhas been measured as (381.3 ± 0.3) ps. Employing segmented detectors for the detection of both annihilation photons allows for the first time to perform a 4D tomographic reconstruction of the annihilation sites including the annihilation lifetime.