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Analysis of Materials
 
 

Forensic technology uses an in-depth knowledge of the composition of materials in order to confirm or eliminate the presence of certain substances. For example, when traces of materials are found at the scene of an incident, analysis is the only possible means of establishing the identity of the substance.  If a substance is made available that can be used for reference purposes, a comparison is made to allow a more detailed identification. Mixed materials or a combination of different materials can increase the likelihood of a possible identification to that of a perfect match.

EDX (energy dispersive X-ray spectroscopy) is a scanning electron microscope (SEM) accessory unit, which is able to provide analysis of materials in a short space of time. Electrons emitted by the electron-beam are focused on the sample material and the attached EDX unit detects the energy transferred, which is processed and presented as a diagram.
This diagram is then evaluated to provide the material analysis. 

WDX (wavelength-dispersive X-ray spectroscopy) analysis takes longer but achieves an even higher degree of accuracy. This is available upon request although not at our own laboratory. 

Inorganic compounds are analyzed using IR/UV spectrometry and for liquid or gaseous substances, a gas chromatograph is used. This equipment is available at co-operating laboratories.   

Technical failure analysis makes use of EDX examinations to establish material defects as the cause of damage, for example when materials fragment. The vast majority of examinations concern the transfer of foreign materials to the incident site, which then either provides the basis for further investigation or can be used as reference for confirmation or elimination purposes.




Site of fracture   Colourless imprint on paper   Material deposit on tip of core pin   Material adhesion  
               

Site of fracture

 

Colourless imprint on paper

 

Material deposit on tip of core pin

 

Material adhesion

 
               
Material defect   Material distortion          
               

Material defect

 

Material distortion

         
               

 

See also articles number 04, 14


04. Forensic examination with a scanning electron microscope
14. Obtaining proof by exclusion



 




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