Dresden 2006 – wissenschaftliches Programm
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VA: Vakuumphysik und Vakuumtechnik
VA 4: Instruments for neutrons
VA 4.9: Vortrag
Montag, 27. März 2006, 17:20–17:40, HSZ 101
Strain mapping by energy selective neutron radiography — •Nikolay Kardjilov1, André Hilger1,2, Ingo Manke1, Markus Strobl1,2, Wolfgang Treimer1,2, and John Banhart1 — 1Hahn Meitner Institut Glienickerstr. 100, 14109 Berlin — 2University of Applied Sciences (TFH) Luxemburger Str. 10, 13353 Berlin
The neutron attenuation coefficient is resulting from different interactions of neutrons with matter. It can be divided into absorption, scattering and diffraction effects attenuating a neutron beam. While all of them are energy dependent especially the diffraction at crystalline and polycrystalline materials has a significant influence on the energy dependence of the attenuation coefficient by introducing so called Bragg-edges to the spectrum of the coefficient. Hence the spectroscopic analyses of the attenuation of a neutron beam passing a polycrystalline sample can identify and quantify crystalline phases, determine applied and residual stresses or the orientation distribution of crystallites. Inserting an energy selecting double monochromator device in the cold neutron radiography instrument (CONRAD) at HMI Berlin enables two dimensional mapping of these spectra on sample sizes up to at least 10 x 10 cm^2 with high spatial resolution. The device accesses a spectrum between 1.94 meV and 15.5 meV including e.g. Fe, Cu and Al Bragg edges. The first results of strain mapping obtained at the neutron radiography instrument CONRAD at HMI using its new energy-selective option will be presented.