The Delta Epsilon LNA0809 is an add-on adapter that extends a GE0809-series combo probe (GE0809C or GE0809CB) with a second, longer-spaced 64" normal resistivity measurement — commonly called "long normal" resistivity in borehole electric logging, complementing the probe's own built-in 16" short-normal reading.

A short electrode spacing (16", built into the base probe) reads a shallow, higher-resolution volume of formation close to the borehole wall — sensitive to thin beds, but also to near-hole effects like drilling-fluid invasion. A long spacing (64", added by this adapter) reads deeper into the undisturbed formation, giving a more representative bulk resistivity at the cost of coarser vertical resolution. Running both together and comparing the two curves helps identify fluid invasion, casing effects, or thin beds being averaged out, and gives more confidence in the true formation resistivity used for porosity, salinity, and lithology interpretation.

Specs: 44.5 mm (1.75") diameter (matches the GE0809 probe body) × 1003 mm (39.5") length, 2.5 kg (5.5 lb). Adds 64" normal resistivity, 0–5000 ohm-m.

Application: Attaches to a GE0809C/GE0809CB combo probe to add long-normal resistivity alongside its built-in short-normal reading, for groundwater and geotechnical borehole logging.

See the Borehole Probes spec sheet for full details.