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Alpha and Gamma Spectrometry

Working Group 6.13


The representation and dissemination of the Becquerel is carried out via activity standards.

For isotopic compositions as well as the analysis of impurities, spectrometric techniques have to be applied, because these techniques are the only ones, that are capable to detect quantitatively different isotopes at the same time.

Therefore PTB operates several specialized spectrometric gamma-ray sensitive detectors, that are optimized for different samples and designed for a high dynamic count rate range.

The alpha spectrometry is structured on the one side in the representation and dissemination of the 222Rn-gas-activity-standards and on the other side the production of specified electrolytical deposited activity standards of alpha emitting nuclides.

Both standards are realized applying the absolute method of counting/spectrometry using well-defined solid angle.

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  • Realization of the unit of activity Becquerel
  • Research and Development in the field of spectrometric measurements procedures and development of new radioactive standards
  • Determination of the emission probability for α-particles and photons
set-up for the measurement of a Thorium-228 PTB activity standard
Fig. 1: Presence and future of the alphaspectrometry applying defined solid angle counting: On the right hand side the present setup with source mounting and aperture system on to the detector system. During the measurement the detector is flush mounted to the exit of the aperture system. On the left hand side the future detector. An electrolytical deposited source (Thorium-228), a typical activity standard of PTB, is on display in the middle.

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  • Activity determination of solid radioactive sources applying α- and γ-spectrometry
  • Determination of the activity concentration (activity divided by mass of solution) of radioactive solutions applying α- and γ-spectrometry
  • Determination of the radioactive isotope impurities of solid or liquid radioactive samples applying α- and γ-spectrometry
  • Fabrication and provision of Radon (222Rn) gas activity standards
  • Measurement and calibration capabilities

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