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Nanostrukturen und Grenzflächen Poster: Do., 13:00–15:30 D-P312
Heavy ion induced damage in alkali halide crystals
irradiated at 8 and 300 K
Kurt Schwartz 1 , Alexander Volkov 2 , Christina Trautmann 1 , Kay-Obbe
Voss 1 , Maik Lang 1 , Michael Sorokin 2 , Reinhard Neumann 1
1 Gesellschaft für Schwerionenforschung (GSI), Planckstr. 1, D 64291 Darmstadt, Germany
– 2 Russian Research Centre Kurchatov Institute, Kurchatov Sq. 1, 123182
Moscow, Russia
Radiation damage in alkali halides induced by swift heavy ions is investigated by optical
spectroscopy, optical bleaching, thermo-stimulated luminescence (TSL), and scanning
force microscopy (SFM). Single crystals of LiF and NaCl were irradiated at the UNI-
LAC linear accelerator of GSI with different heavy ions (from carbon to uranium) in
the energy range between 50 and 2600 MeV. The irradiations were performed from 8
K up to room temperature (RT) using a cryostat that allows additionally in situ absorption
and TSL measurements. The evolution of various color centers was studied
as a function of ion fluence and irradiation temperature [1, 2].
The efficiency of F-center creation strongly depends on the energy loss of the ions and
is related to electron-hole recombination processes [1, 2]. In LiF and NaCl crystals
irradiated at 8 K primary hole centers were observed which are thermally annealed
between 10 and 140 K. In LiF, crystals the ion induced damage changes the electronic
structure of anion excitons [3].
On the surface of irradiated ionic crystals each ion produces a nanometric hillock [4].
The size (height and diameter) of the hillocks depends on the energy loss of the ion
but is independent of the irradiation temperature (8 K, RT) which is in contrast to the
creation of color centers.
The efficiency of color center creation is related to local heating and thermally stimulated
separation of primary color centers in ion tracks. Thermal spike calculations are
performed to describe the heat propagation in the track [2].
[1] K. Schwartz, C. Trautmann, A.S. El-Said, R. Neumann, M. Toulemonde, W.Knolle,
Phys. Rev. B 70 (2004) 184104.
[2] K. Schwartz, A.E. Volkov, K.-O. Voss, M. Sorokin, C. Trautmann, R. Neumann,
Nucl. Instr. Meth. B 245 (2006) 204.
[3] A. Luschchik, A. Kotlov, Ch. Lushchik, V. Nagirnyi, K. Schwartz, E. Vasil´chenko,
Annual Report DESY 2005, Hamburg, 2006, pp. 257 258.
[4] C. Müller, M. Cranney, A.. El-Said, N. Ishikawa, A. Iwase, M. Lang, R. Neumann,
Nucl. Instr. Meth. B 191 (2002) 246.