Sample Holder for Slugs and Bullets
Searching for Striae and Rifle Marks around the Circumference
This substage (or "module") is used for rapid investigation of the surface, to search for marks generated when the bullet or slug passes through a gun or pistol barrel. The specimen is clamped between two spring loaded points, and one of the stage drives of the SEM is connected with the flexible shaft (to the right in the phoot), to allow slow rotation of the generally "cylindrical" specimen. Parallel markings stand at right angle to the direction toward the electron detector.
This way, optimum contrast is generated in secondary or backscattered electrons, providing a tool for the recording of characteristic patterns which can be correlated to or excluded from a given weapon. Interesting locations can be written into the image memory for comparison with previous examinations. This "module" is so small, that it will fit into any SEM, and under a light microscope, or even many types of Atomic Force Microscope (AFM).
If a telescope of the stage mechanics cannot be used, a simple motor drive - in most cases a retrofittable item - may be used alternatively.