Neutrons are a valuable tool for non-destructive material investigation as their interaction cross sections with matter are isotope sensitive and can be used complementary to x-rays. So far, most neutron applications have been limited to large-scale facilities such as nuclear research reactors, spallation sources, and accelerator-driven neutron sources. Here we show the design and optimization of a laser-driven neutron source in the epi-thermal and thermal energy range, which is used for non-invasive material analysis. Neutron resonance spectroscopy, neutron radiography, and neutron resonance imaging with moderated neutrons are demonstrated for investigating samples in terms of isotope composition and thickness. The experimental results encourage applications in non-destructive and isotope-sensitive material analysis and pave the way for compact laser-driven neutron sources with high application potential.
In recent decades the importance of surface roughness as a quality characteristic has increased remarkably. Optical methods for asperity measurements have been investigated, in particular because of their principal advantage of permitting in-process or on -line measurements. This paper reports on a new optical method, the so-called white -light method, which determines a surface parameter, the optical contrast C, that represents the quotient of the standard deviation and mean value of the resultant light intensity. The scanned and converted optical information of a strongly defocused image of the rough surface leads to a good correlation between optically and mechanically evaluated surface parameters. This holds true for surfaces that can be measured without severe distortions due to the mechanical scanning procedure. With reference to industrial applications, the measuring range of this system lies in the interesting region of 0.06 AmSRa_ <10 µm. Efforts are currently being made to bring this type of sensor from the laboratory to the prototype stage for practical use.
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