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NMISA maintains a realisation of Coordinated Universal Time (UTC), called UTC (ZA), for South Africa, Eswatini & Lesotho. The current time is :  

South African Standard Time (SAST) is defined as UTC + 2 hours. The current time is : for South Africa, Eswatini & Lesotho. The current time is :


​​The Radioactivity Stand​ards Laboratory is of critical importance to the South African community that uses radioactivity. A large number of radionuclides are in use today, with many different modes of decay. Since there is no general method of standardisation, the Laboratory personnel need to have the expertise, skills and experience to accurately measure any radionuclide. The Radioactivity Standards Laboratory performs primary activity measurements. The laboratory develops primary methods and also uses secondary standards for measuring radioactivity for different radionuclides. The Laboratory is a full member of the Consultative Committee for Ionising Radiation for Measurement of radionuclides (CCRI(II)) of the CIPM.

The Radioactivity Standards Laboratory maintains the national measurement standard for radioactivity, based on absolute activity techniques.

These techniques incl​​​ude:​

  • TDCR efficiency calculation technique - Measurement of pure beta-emitters and pure electron-capture nuclides.
  • CIEMAT/NIST method – the method is based on tracing with a 3H standard and is available as an alternative for the activity determination of pure beta-emitters.
  • 4πβ-γ and 4π(x,e)-γ coincidence counting-Measurement of the activity of gamma-emitting radionuclides directly.
  • Method for activity determination 125I - double NaI(Tl) coincidence detection system.
  • Ionisation chamber-NMISA Ionisation Chamber is calibrated for a number of radionuclides’.

Servic​​es offered:

  • Absolute standardization of gamma-emitting radionuclides by 4p(LS)b-g coincidence counting (primary method). SANAS accreditation no. 1610.
  • Direct activity measurements of pure beta emitters and pure electron-capture radionuclides by the TDCR efficiency calculation technique (primary method). ANAS accreditation no. 1610.
  • Preparation of various types of radio-active standards by gravimetric transfer of standardized radio-active solutions. on-accredited service.
  • Secondary standards and activity calibrations (using the calibrated Ionization Chamber and balances).   SANAS accreditation no. 1610. This in​cludes calibration of:
    • Activity of I-131 capsules;
    • Activity of Cs-137 check sources;
    • Activity concentration (Bq/g) of various radio-active solutions.
  • On-site calibration verifications of radioactivity (dose) calibrators (well-type ionization chambers) at radio-isotope production facilities and nuclear medicine facilities, using standard reference sources. Non-accredited service.
  • Radio-analysis/ measurement of low-level radioactivity in various sample matrices (e.g. food & environmental samples), using a calibrated HPGe detector. Non-accredited service.
  • Measurement of low-level beta emitter H-3 in w​ater, using Liquid Scintillation Counting. Non-accredited service.​

The Team

​​Name and Surname

Martin van Staden
Section Head: Radioactivity Standard​
​+27 12 947 2799
​Milton van Rooy
Scientist: Radioactivity Standards
​​​​​​+27 12 947 2811
Joline Lubbe ​​​
​Metrologist: Radioactivity Standards
​​​​ ​+27 12 947 2769