Materials characterization using high flux diffraction.

Wroblewski Thomas 

Hamburger Synchrotronstrahlungslabor HASYLAB (HASYLAB), Notkestrasse 85, Hamburg D-22603, Germany

Abstract

Position resolved structural information requires precise definition of the diffracting volume. One approach to achieve this is the use of micro beams from sources of high brilliance like undulator stations at third generation storage rings. An alternative approach requiring only high flux was realized by the novel MAXIM (Materials X-ray IMaging) method in which the diffracting volume is not defined by the primary beam but from the diffracted radiation. It applies a micro channel plate (MCP) as collimator array between sample and a position sensitive detector (PSD) to suppress crossfire of rays diffracted at different sample locations. This micro diffraction on the secondary side permits the illumination of a large specimen area requiring no high brilliance but only flux. Experiments can, therefore, easily be performed on first and second generation synchrotron radiation sources using radiation from bending magnets. Certain experiments can even be done with sealed X-ray tubes. A modified setup using boron silicate capillaries as collimator array has been used with neutrons.
In contrast to conventional diffraction experiments yielding one diffraction pattern in a scan, a series of images is obtained by a MAXIM scan. These data can be rearranged such that up to one million diffraction patterns are obtained, one for each element of the PSD. Powerful algorithms have been developed to reduce this huge amount of data to few diagrams for the characteristic sample features (composition, strain, texture, etc.) and maps showing their spatial distribution. Methods from other disciplines yielding similar data structure (e.g. remote sensing) have been successfully adapted. The MAXIM method allows all kind of investigations that could be performed with conventional methods and even kinetic experiments like the observation of (re-)crystallization processes.

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Presentation: invited oral at E-MRS Fall Meeting 2003, Symposium B, by Wroblewski Thomas
See On-line Journal of E-MRS Fall Meeting 2003

Submitted: 2003-04-22 17:39
Revised:   2009-06-08 12:55
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