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1 PublicationPositron annihilation in flight: experiment with slow and fast positrons
Cizek, J.; Vlcek, M.; Lukac, F.; Melikhova, O.; Prochazka, I.; Anwand, W.; Wagner, A.; Butterling, M.; Krause-Rehberg, R.
Abstract
A novel digital coincidence Doppler broadening (D-CDB) spectrometer was employed for energy resolved investigations of two-quantum annihilation-in-flight (TQAF). The TQAF phenomenon was studied using monoenergetic positrons produced in a slow positron beam and also using fast positrons. Because of a low background the measurements on the slow positron beam could be performed in a close geometry and the TQAF contribution in the two-dimensional gamma ray energy spectra fills a ‘bowl-like’ area delimited by a hyperbolic curve and a kinematical cut-off determined by the kinetic energy of positrons. With decreasing positron energy the area of TQAF contribution becomes smaller and disappears completely for slow positrons with energies below ~ 100 eV. The measurements with fast positrons were restricted to a limited range of angles between the annihilation gamma rays and the TQAF events contribute to a hyperbolic band in gamma ray energy spectrum.
Keywords: positron annihilation in flight; fast and slow positrons
Involved research facilities
- Radiation Source ELBE DOI: 10.17815/jlsrf-2-58
- P-ELBE
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- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 20383) publication
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Journal of Physics: Conference Series 505(2014), 012043
DOI: 10.1088/1742-6596/505/1/012043
Cited 2 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-20383