Carbon-Tape Stub (Tri-Mark)
Definition
A standard SEM-format aluminium or plastic pin stub bearing conductive double-sided carbon tape, used to collect GSR from hands and surfaces for SEM-EDS analysis. The adhesive surface captures and permanently retains particles for months of storage.
- Format
- SEM-format aluminium or plastic pin stub
- Surface
- Conductive double-sided carbon tape
- Use
- GSR collection from hands and surfaces
- Analysis
- SEM-EDS
- Retention
- Permanent capture, stable for months of storage
Common questions
Why must the stub be conductive rather than an ordinary adhesive tape?+
SEM imaging requires a conductive path to prevent electron beam charging on the sample surface. A standard non-conductive adhesive would distort the image and interfere with the EDS elemental analysis used to confirm gunshot residue particles.
How long after a shooting can a viable GSR sample still be collected with this method?+
Detectable particles typically persist on skin for only a few hours under normal activity, though the specific window varies with handwashing, clothing contact, and environmental exposure, which is why timely sampling is prioritized at the scene.
Why does the stub's stability over months of storage matter for casework?+
It allows the collected sample to be transported, queued, and analysed later without degrading the particles, so SEM-EDS examination is not forced to happen immediately after collection, giving labs flexibility to manage casework backlogs.
Related terms
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- Persistence Half-Life (GSR on Hands)
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- Secondary Transfer
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- Tertiary Transfer
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