Shank Length
Shank length is the tip-to-base length of a silicon probe's shank, in millimetres; it caps how deep the sites can be placed, because the shank must clear the dura, any headgear and the tissue above the target.
It is the 5mm in A1x32-5mm-100-177, and it is the number most often confused with site span: a 10 mm shank with 32 sites at 100 µm has 3.1 mm of sites near its tip and 7 mm of bare shank behind them.
Length is chosen from the target's depth plus the tissue above it. Two to three millimetres reaches rodent cortex; 5 mm reaches the rodent hippocampus and striatum; 10 mm and longer reach deep rodent structures and primate cortex, and the Vector design puts a short array on a 70 or 110 mm support body for the deepest targets in large animals. A longer shank is less stiff for the same substrate thickness, so the longest silicon designs are offered at 50 µm or on a support body rather than at 15 µm. Where the sites sit along that length is given by the shallowest and deepest site parameters.
Typical values
| Catalog silicon probes | 1.5 to 60 mm; 5 mm is the median, 5 and 10 mm the most common |
|---|---|
| Vector support body | 70 or 110 mm |
| Design-space parameter | Shank length (shankLenMm) |