A gamma counter is an instrument used to measure gamma radiation in a sample.
Our counters use 12 NaI well-type detectors for high throughput and performance.
A gamma counter uses a scintillation crystal surrounding the sample to detect gamma rays, gamma rays interact with the crystal and are absorbed to produce light. The produced light is then measured by a photomultiplier tube. The energy of gamma rays that can be detected is dependent on the thickness of the crystal. Thin crystals are suitable to detect low-energy gammas, while high-energy gammas need thicker crystals. Gamma counters are not portable, as they need heavy lead shielding to protect the detector from radiation sources other than the sample.
Gamma counters are used to measure samples labelled with a gamma-emitting isotope. Most applications fall into two main groups:
- Radioimmunoassays including RIA, IRMA and others. This includes both the use of radioimmunoassays as a research tool and the quality control of radioimmunoassays.
- Assays such as the Schilling test, Red Cell Mass and Plasma Volume test, GFR (Glomerular Filtration Rate test), and others.