Microdiffraction

this page is still under construction. It will be filled steadily during the next weeks

Motivations and Goals

The applications to micro and nano objects call for intense narrow X-ray beams available at latest generation synchrotron only. The strong demand for structural characterization of objects with ever decreasing sizes has driven the development of new methods to go beyond the average internal structure down to the local structure determination. Probing the local strain, shape (size, orientation) and composition of micro and nano materials are the main objectives of our Laue micro-diffraction setup, this setup being the first in Europe.

The microdiffraction setup is operational since 2006.

Status of the current Microdiffraction Instrument

Our last BeamLine Review Panel occured the 25th and 26th May 2010

A short and general presentation of the microdiffraction setup is available in this page. 

The topics and presentation will be found here (very soon)

MicroBeam performance (20th July 2010)

Lowest beamsize achievable in a reasonable time is routinely (Full-Width-at-Half-Maximum):

horizontally : 0.8 - 0.9 micrometer

vertically : 1 micrometer

Even lowest size may be reached but necessitates much time lost for data collection (KB & mirrors curvatures and illumation optimisation). The entrance KB slits apertures can be reduced but at the expense of the photons flux. Theoretical beamsize (from optics design) expected is 0.5*0.5 µm². 

When using the sample translation stages, sample surface is tilted by 40 degrees with respect to the beam and the horizontal plane. This inclination increase by approximately 50% the actual footprint of the beam in the vertical direction only.

Spectral energy ranges currnetly from 5 to 23 keV

High energy limit can be lowered by changing optics mirrors angles down to typically 12-15 keV. This setup is suitable for disentangling Laue Patterns coming from many grains with large amount of peaks (large unit cell dimensions or/and atoms with high Z values)

Installation and Alignment duration

Installation of the entire setup (KBs , sample translations, CCD, other equipments...) from scratch to microsized white beam delivered to users takes generally 8 hours. First Monochromatic microsized beam setup requires less than 2 hours (optics alignment only). Memorisation of optics motors position allows to switch from white to monochromatic beam (and vice versa) in the range of 15 minutes. Tuning the energy in monochomatic mode can be operated by simply moving only the angle of the monochromator angle: intensity baseline is satisfactorily and smoothly varying over many keV.

Data Analysis -

Laue Microdiffraction Data can be handled and reduced by XMAS software developed by N. Tamura at ALS, Berkeley, California.

We develop our own software package suited for the data collection and analysis on BM32 at ESRF, Grenoble.

LaueTools software package development:

Main page of the project (documentation, installation, bug reports, functionalities inquiry)

Sourceforge.net main page of the project: http://sourceforge.net/projects/lauetools/

Browse the codes: http://lauetools.svn.sourceforge.net/viewvc/lauetools/trunk/

You may have a look at some presentations:

Scisoft Meeting at ESRF:  "LaueTools: a software package for Laue MicroDiffraction Data Analysis"  (29th July 2010)

Laue Microdiffraction: Ecole GDR MECANO Autrans (March 2010) : tutorial

Laue Microdiffraction: Workshop GDR MECANO (september 2009): Automatic analysis: dream or reality ?

Laue Microdiffraction: Workshop GDR MECANO (september 2009): LaueTools

First LAUE Diagram collected:

Intense (black) and elongated (due to penetration of high energy photons) peaks come from Si wafer. Weak and circular spots originate from Cu lines (height=0.5µm, width=3 µm) used as microelectronics interconnects.