Sodium Iodide Scintillation Crystal
The Gamma Ray Tool employs a sensitive sodium iodide scintillation crystal and photomultiplier tube to detect naturally occurring and artificially induced gamma ray radiation. The tool is used for correlation to the surrounding lithology of the well.
Gamma ray logs are useful for recording induced radiation. A tracer log can be used to determine fluid movement by tracing radioactive iodine ejected into the wellbore. Radioactive sand can also be traced to determine the direction of fractures.