A Raman spectrometer for the examination of Questioned documents and other forensic material

Raman spectra exhibit numerous features specific to molecular structure and can provide valuable ‘fingerprints’ for comparing and differentiating materials. Raman spectroscopy using the Foram685-2, is fast, non-destructive, can be performed on materials in situ and requires minimal operator training - an ideal technique for the examination of forensic evidence

The Foram685-2 has a large, A4 size, XY translation stage with fine spatial adjustment to allow the operator to align the laser probe on to samples as small as 5 microns in diameter. Sample selection is assisted by the use of an integral video microscope with a rotating turret, that can be fitted with up to four objective lenses to provide on screen magnification of up to 500×.

To protect samples from laser induced heat damage the Foram685-2 is fitted with a low power, 4.5mW, laser and intensity controls to permit operation as low as 10% of maximum output. Signal integration compensates for low signal intensity.

The PC operating system has a comprehensive software package providing:

• easy to use on screen menus
• advanced signal processing for maximum sensitivity
• an automatic spectral comparison technique based on peak correlation
• data archiving with search and match facilities

Other functions include baseline correction to remove background fluorescence from spectra and peak labelling for easy-to-read printouts.

Foram685-2 is also supplied with reagents to carry out surface enhanced resonant Raman scattering (SERRS).
Specifications include:

• external cavity laser, 685nm emission
• 400 to 2000cm^-1 spectral range
• 8cm^-1 spectral resolution
• cooled CCD array detector

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