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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 15: Poster: New Instruments and Methods

CPP 15.17: Poster

Dienstag, 27. März 2012, 18:15–20:15, Poster A

Field-cycling NMR based analysis of the damage structure in Ionic crystals irradiated with swift heavy ions irradiated with swift heavy ions — •Michael Ditter, Simon Quittek, and Franz Fujara — Institut für Festkörperphysik, TU Darmstadt

Radiation damage in ionic crystals such as lithium fluoride has been extensively studied in the past, however so far no heavy ion irradiated samples were examined with field-cycling (FC) NMR. In lithium fluoride the nuclear spin lattice relaxation time is decisively influenced by the presence of paramagnetic impurities and defects like F-centers, induced by swift heavy ion irradiation. Most of these defects are concentrated in a halo around the ion tracks. Besides defects created directly by the projectiles secondary radiation, originating during the stopping process inside the crystal, causes damage beyond the ion range. For the full examination of this effect a spatial resolution, as offered by one of our FC spectrometers, is desirable. The distribution of the defects is thought to be mainly responsible for the observed magnetic field dependence of the relaxation rate. Thus NMR relaxometry, especially field-cycling techniques, is a suitable tool to gather information about the structure of radiation damage. Additionally NMR spectroscopy can be used to detect the presence of molecular fluorine and lithium colloids in the damaged zones. Our results obtained by these methods will be presented.