The Inter-Agency Committee on Radiation Safety-30 years of international coordination of radiation protection and safety matters.

The Inter-Agency Committee on Radiation Safety (IACRS) was constituted in 1990, as a forum for collaboration and coordination between international bodies with regards to radiation safety. It consists today of representatives of eight intergovernmental member organizations (the European Commision, Food and Agriculture Organization, International Atomic Energy Agency (IAEA), International Labour Office, Organisation for Economic Co-operation and Development/ Nuclear Energy Agency (OECD/NEA), Pan American Health Organization, United Nations Scientific Committee on the Effects of Atomic Radiation and the World Health Organization) and five observer non-governmental organizations (International Commission on Radiological Protection, International Commission on Radiation Units & Measurements, International Electrotechnical Commission, International Radiation Protection Association and International Organization for Standardization). The IACRS provides a platform for interaction between these relevant international bodies to contribute to a common understanding of the scientific basis and legal framework for the application of the system of radiation protection, towards global harmonisation of radiation safety standards.

EVOLUTION OF THE IEC AND EN STANDARDS FOR INDIVIDUAL MONITORING OF IONISING RADIATION.

This article presents the evolution of the International Electrotechnical Commission (IEC) and the European standards for individual monitoring of ionising radiation issued, respectively, from the committees IEC/Sub Committee 45B and European Committee for Electro-technical Standardization/Technical Committee 45B 'Radiation protection instrumentation'. Standards for passive individual photon and beta dosimetry systems as well as those for active individual monitors are discussed. A neutron ambient dose equivalent (rate) meter standard and a technical report concerning the determination of uncertainty in measurement are also covered.

Experience on evaluation of passive neutron dosemeters according to ISO 21909.

This paper presents experience, found problems and lessons learnt during the evaluations of various TLD and CR-39 passive neutron dosemeters according to ISO 21909. Recommendations for the standard, being currently in revision, are also discussed.

IEC standards for individual monitoring of ionising radiation.

This paper presents IEC/SC 45B 'Radiation protection instrumentation' and its standards for individual monitoring of ionising radiation: IEC 61526 Ed. 3 for active personal dosemeters and IEC 62387-1 for passive integrating dosimetry systems. The transposition of these standards as CENELEC (European) standards is also discussed together with the collaboration between IEC/SC 45B and ISO/TC 85/SC 2.

Radon emanation measurements using silicon photodiode detectors.

Driven by the global concern about radon hazards, a wide variety of methods to measure radon and its decay products have been developed. Pin silicon photodiodes are increasingly applied in this field, their main advantages being high detection efficiency for alpha particles and low cost. In this paper, we present a system to determine the emanation factor for 222Rn from porous material based on a pin photodiode.

Thermoluminescence measurements of neutron dose around a medical linac.

The photoncutron ambient dose around a 18 MV medical electron lineal accelerator has been measured with LiF:Mg,Ti chips of 3 x 3 x 1 mm inside moderating spheres. During the measurements a water phantom was irradiated in a field of 40 x 40 cm2. Two methods have been considered for comparison.

Response components of LiF:Mg,Ti around a moderated Am-Be neutron source.

The responses of TLD-1010, TLD-700 and TLD-600 thermoluminescence dosemeters to the radiation field inside a water tank enclosing an isotopic 241Am-Be neutron source are analysed. Separate contributions coming from thermal neutrons, neutrons with energies above thermal and gamma rays to the total response of the three types of TLD are obtained. This is accomplished by assuming that the gamma responses for materials with different 6Li enrichments are identical and that the neutron response of TLD-700 is negligible compared to TLD-100 and TLD-600.

Simulation of the radon and radon progeny detection by silicon photodiodes.

The use of silicon photodiodes for field radon measurements requires the utilization of measuring cells for protection against environmental electromagnetic fields. It is very important to study and optimize the impact of geometry conditions (dimensions of the measuring cell) on the photodiode detection efficiency that can be reduced more than 10-30 times. Two models (for volume-distributed nuclides around the detector and for radon progeny deposited on the diode surface radon progeny) were applied for simulation of the photodiode detection in measuring cells of different sizes.

The use of silicon photodiodes for radon and progeny measurements.

Reduced cost, high quantum efficiency and very good detection characteristics of PIN silicon photodiodes made possible their utilization for alpha particles detection. This paper presents different studies and applications of this type of detector for qualification and quantification of radon and its progeny in laboratory and in the field. Since photodiodes are sensitive to environmental electromagnetic fields, protecting cells were adapted for use around the detector.