Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

The Helmholtz-Center at Dresden-Rossendorf operates several user beamlines for materials research using positron annihilation energy and lifetime spectroscopy. A superconducting electron LINAC [1] serves as a driver for hard X-ray production from electron-bremsstrahlung which in turn generates positrons through pair production. GiPS, the Gamma-induced Positron Source directly generates electron-positron pairs inside the sample under investigation [2]. The source is especially suited for materials which are not qualified for vacuum conditions or because they are imposing hazardous conditions or intrinsic radioactivity. Some exemplary defect studies [3] will be presented. MePS, the Monoenergetic Positron Source utilizes positrons with discrete energies ranging from 500 eV to 16 keV [4] for thin film studies. A magnetic beam transport system guides positrons to the sample under investigation. Applications of porosimetry studies in low-k dielectrics [5] and polymer brushes [6] will be presented. The MePS facility is currently complemented by the AIDA-II - Apparatus for in-situ Defect Analysis - where defect studies can be performed in a wide temperature range during thin film growth and ion irradiation. The precedent setup AIDA-I is in operation at a 22Na-based mono-energetic continuous positron beam [7] used for Doppler-broadening spectroscopy experiments [8,9].
The MePS facility has partly been funded by the Federal Ministry of Education and Research (BMBF) with the grant PosiAnalyse (05K2013). AIDA-I was funded by the Impulse- und Networking fund of the Helmholtz-Association (FKZ VH-VI-442 Memriox). The AIDA-II facility was funded through the Helmholtz Energy Materials Characterization Platform.

[1] F. Gabriel, et al., Nucl. Instr. Meth. B 161, 1143 (2000).
[2] M. Butterling, et al., Nucl. Instr. Meth. B 269, 2623 (2011).
[3] M. Reiner, et al., Scientific Reports 6, 29109 (2016).
[4] A. Wagner, et al., Journal of Physics: Conference Series 791, 012004 (2017).
[5] A. Uedono, et al., Applied Surface Science 368, 272 (2016).
[6] G. Panzarasa, et al., Macromolecules 50, 5574 (2017).
[7] W. Anwand, et al., Defect and Diffusion Forum Vl. 331, 25 (2012).
[8] M. O. Liedke, et al., Journal of Applied Physics 117 163908 (2015).
[9] T. Kosub, et al., Nature Communications 8, 13985 (2017).