Regensburg 2004 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 3: Magnetic Resonance

CPP 3.4: Vortrag

Montag, 8. März 2004, 10:45–11:00, H 38

Radio frequency ESR imaging — •Marco Ulrich and Elmar Dormann — Physikalisches Institut Universit"t Karlsruhe (TH), D-76128 Karlsruhe

During the last years the Magnetic Resonance Imaging (MRI) became to one of the most important imaging methods especially in medical techniques. Although this technology is mostly based on protons (NMR-Imaging), it is in principle also possible to use ESR signals for producing images. In this case the radical cation salt (Fluoranthene)_2PF_6 as an organic quasi-1d conductor has ideal properties for this so called ESR-Imaging. Two different methods of 2D-ESR imaging of these (Fluoranthene)_2PF_6 crystals could be realized. The Projection Reconstruction (PR) is operating with two variable but static gradients which are orthogonal to each other. On the other hand the Fourier Imaging (FI) is using one static and one pulsed gradient to achieve the necessary spatial encoding of the ESR signals which is the root of the whole imaging process. Finally a tomographical software is reconstructing the images. In both cases the big advantage of using pulsed ESR technology instead of CW ESR is that it is also possible to get further information about dynamical parameters like the transversal relaxation time T_2 or spin diffusion constants of the analyzed material. The variation of the ESR images with the temperature around the Peierls transition could also be shown.