Intercomparison of the personal dose equivalent for photon radiation

Project Description

The Technical Protocol of this comparison was sent to the 16 participants in December 2003. In the protocol a detailed time schedule is given. All participants have agreed to the protocol. As planned in January 2004 the comparison started. According to the time schedule the first participant is the pilote laboratory (PTB), which has performed the measurements in January. At the end of March 2004 the measuring protocol of the pilote laboratory was sent to the EUROMET TC-IR Chairman Nelcy Coursol as arranged in the technical protocol.At the beginning of February the measuring instruments of the comparison was sent to the next partner, Bundesamt für Eich- und Vermessungswesen (BEV) in Austria. There, the measurements were carried out successfully in February and March. The measuring devices were sent back to the PTB for testing at the beginning of April as agreed in the technical protocol. The measuring protocol from the BEV was sent to the pilote laboratory (PTB) at the end of April.Now the measuring devices are tested in the PTB and will be sent in Mai to the next participant, OMH in Hungary. In summary, the comparison runs as planned and without problems. The concept of radiation protection quantities developed by ICRU between 1985 and 1993 was adopted by the European Union in Council Directive 96/29/Euratom. The personal dose equivalent, Hp(10), was introduced as the operational quantity for individual monitoring. With the transfer of this directive into the national law of the EU member states, the national standard laboratories must be able to realise and disseminate this unit. A first comparison for Hp(10) initiated by the BEV was performed as an EA-Interlaboratory Comparison using the radiation quality S-Cs (Eph = 662 keV) and normal beam incidence. However, the representation and dissemination of the personal dose equivalent Hp(10) is difficult for photon energies lower than 30 keV because of its strong energy and angle dependence in this range. In the comparison proposed calibrations at different angles of incidence and at some radiation qualities of the ISO narrow spectrum series with low and high mean energies should be performed (N-15, 0°; N-20, 45°; N-30, 75°; N-60, 0°; N-120, 0°). For quality assurance of the dissemination of Hp(10) is a comparison using different angles of incidence and radiation qualities in a wide energy range very important.A secondary standard ionisation chamber for Hp(10) will be used as a transfer instrument circulating between the participants. Together with the chamber a complete electronic measuring system will circulate. It is planned that both the chamber and the electronic system will be sent back from each participant to the coordinator for testing. The responses will be the comparison parameter. The full programme of this comparison with more details about the measuring conditions is attached to this proposal. It is planned that participants, who cannot perform the whole programme, can take part with only some of the radiation qualities of the comparison.

Publication: iopscience.iop.org/0026-1394/49/1A/06015/


Progress Report, 16 November 2005

In July 2005 the PSI /CH (contact person: Dr. C. Schuler) was included additionally in the comparison after all partners have consented. Now, 17 partners take part in the comparison. Besides, ENEA / IT could not perform the measurements in the time range planned (09.2005 – 10.2005) and BNM-LNHB / FR wanted another date as laid down in the time schedule. For these reasons, the course was reorganized. It could be reached that the duration of the comparison is only one month longer (now: 12/2007) and no delay results. All participants agree with the changes.

Up to now 8 partners (PTB / DE, BEV / AT, OMH / HU, IAEA, NPL / GB, HAEC / GR, STUK / FI, CIEMAT / ES) have performed their measurements without problems. The measuring devices are now at the ninth partner (ITN / PT).

A first evaluation of the measuring results given in the protocols of the first four partners was done. It could be demonstrated that the data given in the protocols are sufficient for a successful evaluation. The results were presented in anonymous form at the conference IM 2005 in Vienna (April 2005) in a talk and a paper. Before, all participants got the results in anonymous form.

The comparison is running without problems and is on time.

Further Information

Progress report submitted 18th May 2004. Bilateral comparison for the personal dose equivalent, Hp(10), between the PTB and the BEV in the run-up to the EA-Interlaboratory Comparison IR4, publication: EUROMET.RI(I)?S1: personal dose equivalent comparison between the BEV and the PTB, Metrologia, 39, Tech. Suppl. 06010, 1 – 13 (2002)