The QL40GRA-1000 natural gamma probe sub can be run stand-alone, or with other QL tools in a custom stack. The natural gamma crystal is a proven 22mm diameter x 73mm long Na(Th)I scintillation crystal, suitable for general lithology applications and uranium exploration.
Other QL probes commonly stacked with the QL40GRA include the QL40RES (8-16-32-64” normal resistivity), QL40FTC-B (temperature / fluid resistivity), and the QL40CAL (3-arm caliper). But many possibilities exist owning to the flexibility of the QL (Quick Link) family of geophysical logging probe functions. Natural gamma logs can be run in any borehole environment, cased, uncased.
Above shows Typical GR responses and data display (right)The QL40-GRA tool is equipped with a scintillation Thallium doped Sodium Iodide crystal - NaI(Tl), which, when hit by gamma rays, emits pulses of light. These pulses of light are amplified by a photo multiplier tube and are then converted into electrical pulses. The number of pulses are counted, digitised and transmitted up the wireline to the surface acquisition system