Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

HK: Physik der Hadronen und Kerne

HK 4: Instrumentation und Anwendungen I

HK 4.13: Vortrag

Montag, 17. März 2003, 19:00–19:15, C

Investigation of multi–wave x–ray interference phenomena in crystals at the Mainz Microtron MAMI — •A. Sharafutdinov, C. Ay, H. Backe, N. Clawiter, M. El Ghazaly, K.-H. Kaiser, G. Kube, W. Lauth, H. Mannweiler, and T. Weber — Institut für Kernphysik, Universität Mainz, J.-J. Becher Weg 45, 55099 Mainz

In a cubic lattice structure, like that of a silicon single crystal, the energy of the ⟨nnn⟩–Bragg reflection in backward direction coincides with the energy of a ⟨hkl⟩ reflection if the condition h2+k2+l2 = n(h+k+l) is fulfilled. This equation is satisfied, e.g., for n=3, h=k=1, l=-1, or n=3, h=k=2, l=4. Together with the cyclic permutations of these solutions seven beams are able to interfere in backward direction. Multi–wave x–ray interference phenomena occur which have been studied at MAMI. Parametric x radiation and diffracted transition radiation have been observed when the 855 MeV electron beam passes through silicon single crystals of thicknesses between 50 µm and 525 µm. Angular distributions of (111), (333), (444), and (555) reflections have been recorded with a 0.3 mm thick pn–CCD detector of 10x30 mm2 size which was located in 11.5 m distance from the target. Pronounced interference structures have been observed in the angular distribution, in particular of the (333) reflection at photon energy of ℏω = 5.96 keV, which surprisingly depend on the orientation of the corresponding reciprocal lattice vector with respect to the crystal surface normal. An overview of the experimental results will be presented.


Work supported by the DFG under contract BA 1336/1-3

100% | Bildschirmansicht | English Version | Kontakt/Impressum/Datenschutz
DPG-Physik > DPG-Verhandlungen > 2003 > Tübingen