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HK: Physik der Hadronen und Kerne

HK 14: Instrumentation und Anwendungen II

HK 14.6: Group Report

Monday, March 22, 1999, 18:15–18:30, F

Near-axis channeling radiation of 31 MeV electrons in silicon — •Rainer Kotthaus¹, Gerd Buschhorn¹, Matthias Rzepka¹, Klaus Schmidt¹, Peter Weinmann¹, Jörg Freudenberg², Harald Genz², Victor Morokhovskii², and Achim Richter² — ¹Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, D-80805 München — ²Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr. 9, D-64289 Darmstadt

The spectral-angular and the linear polarization properties of channeling radiation emitted by 30.8 MeV electrons incident on a 13µ m thick silicon crystal at small angles with respect to various major crystal axes have been investigated both experimentally at S-DALINAC and theoretically by potential model calculations. The transition from axial to planar channeling radiation properties is well described by a two-dimensional many-beam calculation based on a periodic string potential.

Channeling radiation of rotationally symmetric axes (e.g. the ⟨ 100 ⟩ axis) is not linearly polarized whereas radiation produced at axes of azimuthal asymmetry (e.g. the ⟨ 110 ⟩ axis) shows a small amount of linear polarization. At energies above the strongest planar channeling radiation lines coherent bremsstrahlung linearly polarized perpendicular to the polarization of the corresponding planar channeling radiation is observed and found to be well reproduced by the model calculations.