EURADOS Intercomparison 2009 for extremity dosemeters

EURADOS was created to be a scientific network of European laboratories involved in research in radiation dosimetry. The objective is to advance the scientific understanding and the technical development of the dosimetry of ionising radiation by stimulating collaboration between European facilities.

Over the last decade, EURADOS has coordinated the working group on Harmonisation of Individual monitoring in Europe (WG2) entrusting them different tasks along the time. With the aim to improve the harmonization of individual monitoring and help the individual monitoring services (IMS) to comply with ISO 17025 standard, the subgroup 2 (WG2-SG2) was assigned to set up a self sustained programme of intercomparisons in Europe.

As a result of this work, EURADOS has successfully executed the EURADOS Intercomparison 2008 for whole body dosemeters. As a next step in the programme EURADOS has executed the EURADOS Intercomparison 2009 for extremity dosemeters.

Scope

The intercomparison concerned to extremity dosemeters intended to estimate H_p(0,07). The dosemeters were of type ring, stall or wrist, designed to be worn on fingers, wrist or ankle, and are being used routinely in individual monitoring of exposed workers.

Irradiations, restricted to photons and betas, will be performed in European accredited irradiation facilities in terms of H_p(0,07) in the following ranges:

1.       Photon energy: 16 to 662 keV

2.       Beta mean energy: 250 to 935 keV

3.       Dose: 0,5 mSv to 1 Sv

4.       Angle of incidence: ± 60º

The dosemeters will be irradiated with both photon and beta sources but the participant may choose to include only the results for photons or betas in the Certificate of Participation by marking this option the the application form.

Intercomparison procedure

The candidate participant fills in the Application Form (). The Organization Group registers the applications. The Organization Group informs the candidate participant about the acceptance of their application.

The participant received an invoice from EURADOS in order to transfer a participation fee of 1250 Euro to Eurados bank account. The fee was calculated on a non-profit base and any surplus money will be used primarily for the purpose of harmonisation in individual monitoring and maintaining the expertise in this field within EURADOS .

After receipt of the participation fee, the Organization Group provided the participant with detailed instructions and guidelines for preparing and labelling the dosemeters and for sending the dosemeters to the coordinating laboratory (NRG Arnhem, Netherlands).

For this intercomparison a total of 28 dosemeters from each participant IMS is needed:

1.       22 dosemeters for irradiation

2.       4 transit dosemeters for background control

3.       2 spare dosemeters

After performing irradiations, the coordinating laboratory sent back the dosemeters to the participant for readout. Within one month after receiving the dosemeters, the participant sent back the results in terms of H_p(0,07) in a response form provided by the Organization Group.

After all participants had submitted their results, the Organization Group sent the participant the irradiation data and response values. Revision of results after distribution of the irradiation data was only possible in case of errors made by the irradiation lab or intercomparison organization (to be judged by the Organization Group; in this intercomparison there were no revisions made).

After confirmation of the results, EURADOS provided the participant with a “Certificate of Participation” including information on the irradiation qualities, doses imparted, response values and overall uncertainties for all irradiations (or for photons or betas only if this option was chosen in the application form).

Intercomparison report

The Organization Group prepared a paper summarizing the results of the intercomparison, which was presented at the Individual Monitoring Conference (IM2010), 8-12 March 2010, in Athens. In addition, the participants were offered the opportunity to collect their certificates at the participants meeting, which was held as a satellite meeting of this conference, and to discuss the results among the Organization Group and the participants at this meeting. A summary of the results and additional information about the irradiations presented in Athens are available to download. These results must be considered as preliminary, because the paper was submitted to the conference organizers to be published in the conference proceedings and is currently being processed in the review process.

In addition the Organization Group will prepare a report summarizing the results of the intercomparison. The report will mention the name of the IMS that participated and the type of dosemeter used but the results will be given anonymously. It is planned to publish this report as an EURADOS report.

Intercomparison results are considered by EURADOS as confidential data and only will be used with statistical purposes for technical and scientific studies. The Organization Group will sign a confidentiality clause and both the identity of the participants and the reference data will be known only to a minimum of persons within the Organization Group.

Time Schedule