Through our two primary measurement techniques called 4πβ-γ coincidence counting and the Triple-to-Double Coincidence Ratio (TDCR) technique, we standardize β- and γ-emitting radionuclide solutions using liquid scintillation counting. Our standardized radionuclide solutions have very accurate activities with standard uncertainties which are usually better than 1 %. A standardized radionuclide solution can then be used to provide secondary services which are traceable to the primary techniques.
Ionization Chamber (IC)
From standardized radionuclide solutions, various calibration sources can be prepared for the NMISA IC and calibration factors determined, through which secondary measurements can be performed. Through this process a primary measurement result is maintained through the IC. Calibration sources can also be prepared for clients such as hospitals and isotope production facilities that use radioactivity dose-calibrators and calibration factors. For example, nuclear medicine such as I-131 capsules can also be standardized.
High-Purity Germanium (HPGe) Detectors
In a similar manner two HPGe detectors are calibrated and employed for γ-ray spectrometry. The HPGe detectors are mainly used for low-level measurements to monitor environmental samples from the Koeberg nuclear power station for higher than acceptable levels of Cs-134, Cs-137 and I-131. We can also measure consumer products for radioactive contamination. The same applies for any other kind of sample that needs testing for contamination or impurities, except gasses.
Commercial Liquid Scintillation Counter
A calibrated commercial liquid scintillation counter is also employed for low-level measurements of β-emitting radionuclides of environmental samples. Samples are most commonly analysed for H-3 and Sr-90.
Calibration sources in various geometries of liquid or solid material can be prepared through accurate weighing of primary standardized radionuclide solutions. Some of these geometries include button/point sources, Marinelli sources, sources in glass ampoules and vials. Depending on the client's needs, we can prepare sources with typical standard uncertainties between 1 % and 10 %.