Forensics

Forensics laboratories, by their very nature, need to have the capability to analyze a variety of sample types and exhibits. FEI's Forensic SEM solution provides this flexibility by offering the ability to operate in different imaging modes—high-vacuum, low-vacuum, and environmental—thus allowing samples to be examined in their natural state with no special preparation required, resulting in substantial time and cost savings. Even non-conducting, out-gassing, dirty, oily, or wet samples can be examined non-destructively – there is no requirement for coating, cutting, drying, cleaning or manipulation.  
In addition to conventional, high-vacuum imaging, the system enables the specimen surface to be imaged in a gaseous environment, or at varying sample chamber pressures for Secondary Electron detection, elemental content, or topographic contrast. Gas in the chamber eliminates the charging effects of the uncoated sample, and dedicated detectors use gas to aid the imaging process. EDS X-ray microanalysis is also available with this solution.

The availability of DualBeam™ systems allows forensic researches to reveal details below the surface. Dual beam instruments combine the high resolution imaging capability of SEM with the cross sectioning and sample manipulation capabilities of a focused ion beam (FIB).

Forensic Geoscience 

Firearm discharge residue (FDR) is a general term to describe the burnt, partially burnt, and unburnt particles that arise following the firing of a gun. A number of sources are known to contribute to the composition of the residue, including the explosive primer, the propellant, the bullet, the cartridge case and the weapon used. Particles generated by the explosion of the primer are called Gunshot Residue (GSR) particles.

GSR samples are best imaged by a SEM fitted with EDS micro-analysis capabilities as the particles are typically very small (micron-sized) and have distinctive chemical compositions, size and shape. FEI has leveraged its technology expertise and leadership in high-resolution imaging and microanalysis to create powerful systems and applications that work together as complete forensic solutions. Working extensively with the worldwide forensics community to understand the unique challenges and application requirements of forensic science, FEI engineers and application specialists have designed and manufactured the next generation of forensic microscopy tools to help investigators maintain the evidentiary validity of the proof and the integrity of the samples.

FEI Forensic SEM Solutions use state-of-the-art EDS detectors, based on Silicon Drift Technology, combined with Field Emission Gun SEM sources that supply high beam currents for fast and efficient throughput. Fully integrated software, GSR Magnum™ , allows the analyst to measure and classify the gunshot residue particles, and the high-precision, motorized stage of the SEM allows for a rapid return to the field of interest, center and magnify to selected particles for thorough analysis and reconfirmation.

A critical aspect of GSR analysis is the validation of results to ensure reliability. In order to address this, FEI uses GSR test standards (Plano GmbH, Germany) in combination with dedicated software (microValidator™), which quickly and accurately allows the operator to check the system and diagnose issues such as misalignment or incorrect calibration.

Microscopes for Forensics:

• Forensic SEM 
• GSR SEM    
• GSR F50 
• GSR S50    
• GSR Magnum    
• Microvalidator     

Applications for Materials Science:

• Materials Imaging, Analysis and Characterization
• In situ Dynamic Observation and Imaging
• Prototyping for MEMS and NEMS
• Site-specific Sample Preparation