Measurement tools
Lower levels of radioactivity are normally measured in scintillation detectors - either sodium iodide crystal-based gamma counters for gamma emitters or liquid scintillation counters for beta emitters.
Gamma counters are based on sodium iodide scintillation detectors. They are used to measure small (Bq-KBq) amounts of radioactivity which they record in terms of 'counts per second'. Gamma counters are commonly automated to enable them to count many samples in succession and are computer controlled. They are often used for counting low activity clinical samples such as blood or urine, swabs used for wipe tests, or, in QC, for counting low activity TLC strips cut up into several pieces.
Beta counters are liquid scintillation detectors, and are used to count radioisotopes, such as 14C, 3H and 32P, that emit beta radiation. They can also detect the auger electrons emitted from radioisotopes such as 51Cr and 125I.
Gamma counter:
