Primary activity measurements with a 4πβ-4πγ coincidence counting system

Appl Radiat Isot. 2012 Jan;70(1):249-56. doi: 10.1016/j.apradiso.2011.07.017. Epub 2011 Aug 4.


The radioactive concentrations of (166m)Ho, (134)Cs and (133)Ba solutions have been standardised using a 4πβ-4πγ coincidence counting system we have recently set up. The detection in the beta channel is performed using various geometries of a UPS-89 plastic scintillator optically coupled to a selected low-noise 1in. diameter photomultiplier tube. The light-tight thin capsule that encloses this beta detector is housed within the well of a 5in.×5in. NaI(Tl) monocrystal detector. The beta detection efficiency can be varied either by optical filtering or electronic discrimination when the electrons loose all their energy in the plastic scintillator. This 4πβ-4πγ coincidence system improves on our 4πβ(PC)-γ system in that its sample preparation is less labour intensive, it yields larger beta- and gamma-counting efficiencies thus enabling the standardisation of low activity sources with good statistics in reasonable time, and it makes standardising short-lived radionuclides easier. The resulting radioactive concentrations of (166m)Ho, (134)Cs and (133)Ba are found to agree with those measured with other primary measurement methods thus validating our 4πβ-4πγ coincidence counting system.

MeSH terms

  • Equipment Design
  • Equipment Failure Analysis
  • Radioisotopes / analysis*
  • Radiometry / instrumentation*
  • Scintillation Counting / instrumentation*
  • Sensitivity and Specificity
  • Transducers*


  • Radioisotopes