Forensic science, the application of science to law, extends beyond studying DNA samples to include the microscopic analysis of more diverse bodies of evidence, such as gunshot residue, clothing fibers, handwriting samples, and car paint chips. The need to more accurately and rapidly identify and analyze crime-scene samples with high-resolution detail is increasing, as more sophisticated criminals and new types of evidence challenge existing forensics tools and techniques.
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 technical 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.
Because forensics labs handle such disparate types of samples, FEI tools for forensics allow scientists to examine virtually any sample in an environmental scanning electron microscope (ESEM) chamber, so it can be analyzed in its natural state.
Forensic Platforms
The Forensic Scanning Electron Microscope (SEM) and the Gun Shot Residue (GSR) Analyzers are flexible platforms that allow forensic specialists to focus on microscopic traces of evidence using imaging, comparison, and X-ray microanalysis (EDS) techniques.
The Forensic SEM offers different imaging modes—high-vacuum, low-vacuum, and environmental—so samples can be analyzed 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 nondestructively; no coating, cutting, drying, cleaning, or manipulation is necessary.
In addition to conventional, high-vacuum imaging, the systems enables specimen surface imaging in a gaseous environment or at varying sample chamber pressures for secondary electron detection, elemental contrast, 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. Traditional techniques as EDS can be applied.
Both the GSR S50 and the GSR F50 are engineered for the automated analysis and classification of gunshot residue. Both systems are equipped with state of the art EDS detectors based on Silicon Drift Technology, the latter system is equipped with a Field Emission Gun to supply extreme high beam currents for even faster throughput. The application-oriented tools have a fully integrated GSR Magnum software package to analyze and classify gunshot residue. Its high-precision, motorized stage can return to the field of interest and then center and magnify the selected particle for thorough analysis and reconfirmation.
Validation
A critical aspect of the SEM/EDS system, including GSR analysis, is validation to ensure reliable results when using the tools on a day to day basis. To ensure reliable results, the systems behavior needs to be diagnosed in fixed intervals. Special GSR test standards (Plano GmbH, Germany) are available and designed for the adjustment, calibration and validation of analytical SEM/EDS systems when used for automatic analysis of GSR particles. Special validation software helps to diagnose the system for many vital points in order to guarantee a correct performance. The microValidator™ reports any error or misalignment and is the perfect tool for diagnosing your SEM/EDS/GSR analysis system.
Forensics Resources and Web Links
Explore the links below for more forensics resources available online: