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Extensions to the Beta Secondary Standard BSS 2


For several years, the irradiation facility for beta radiation, the Beta Secondary Standard BSS 2 developed at PTB, has been in worldwide use to perform irradiations with calibrated beta sources [1].

Recently, the following extensions have been added in order to meet new challenges in radiation protection:

  1. Possibility of using a 106Ru/106Rh beta source (used in eye tumour therapy) which has got a higher beta endpoint energy of 3.5 MeV instead of 2.3 MeV of 90Sr/90Y;
  2. Inclusion of the (small) contribution due to photon radiation;
  3. Implementation of the quantity personal dose equivalent at a depth of 3 mm, Hp(3), which is important to monitor the eye lens dose;
  4. Improvement of the correction for ambient conditions (air temperature, pressure, and relative humidity);
  5. Checksum test to secure the calibration data;
  6. Connection of the PC and the BSS 2 via network interface (TCP/IP) once the electronic unit of the BSS 2 was modified. This is of importance as the old type of connection (parallel and serial com-port) are not available in any more all modern computers;
  7. Distribution of the BSS 2 with a rod phantom (for the irradiation of finger ring dosemeters).

All these extensions have been implemented at the PTB’s BSS 2 example. The routine implementation of extension 1 is still under investigation by the manufacturer. The new examples of the commercially available BSS 2 already contain extensions 2 to 7. Extensions 2 to 4 are also available for old BSS 2 examples via a software update free of charge. All extensions have been published [2]. The figure shows the new BSS 2.

This work was financially supported by the Bundesministerium für Wirtschaft und Technologie by the project "Innovation mit Normen und Standards - INS" "Verbesserung der Überwachung der Dosis der Augenlinse".


  1. P. Ambrosi, G. Buchholz and K. Helmstädter:
    The PTB Beta Secondary Standard BSS 2 for radiation protection
    J. Instrum. 2 P11002 (2007)
  2. R. Behrens und G. Buchholz:
    Extensions to the Beta Secondary Standard BSS 2
    J. Instrum. 6 P11007 (2011)
    , J. Instrum. 7 E04001 (2012), J. Instrum. 7 A05001 (2012)
    A complete version is also Initiates file downloadavailable.