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Purpose Selective internal radiation therapy (SIRT) is a treatment for various kinds of liver tumours by injecting 90 Y bearing microspheres into the liver vessels. To perform meaningful post-treatment dosimetry , quantitative imaging is performed. Methods This work uses a Monte-Carlo based reconstruction software with scatter and attenuation correction and collimator modelling that allows the quantification of 90 Y bremsstrahlung SPECT/CT data. A dataset comprising 17 patients and measurements on a Jaszczak phantom, a NEMA IEC Body phantom and an anthropomorphic liver phantom are analysed and activities and dose values are acquired. These measured values are compared with applied activities and pre-treatment calculations, allowing to assess the quality of the SPECT reconstruction. A detailed uncertainty budget is presented, including uncertainties of the dose calibrator, the count rate, non-included interactions and other factors. Results The applied method is validated by finding measurements repeatable within the given uncertainty, and it is shown the influence of various parameters on the reconstruction process is negligible. Furthermore, activities and doses measured in the phantoms show good agreement with calculated values, if they are corrected for partial volume effects . Conclusions The strict observation of metrological requirements and the creation of an uncertainty budget increase the reliability and traceability of this novel approach to 90Y dosimetry. It gives an example of successful voxel-based dosimetry based on quantitative 90Y SPECT/CT image data.

An interlaboratory comparison for European radon calibration facilities was conducted to evaluate the establishment of a harmonized quality level for the activity concentration of radon in air and to demonstrate the performance of the facilities when calibrating measurement instruments for radon. Fifteen calibration facilities from 13 different European countries participated. They represented different levels in the metrological hierarchy: national metrology institutes and designated institutes, national authorities for radiation protection and participants from universities. The interlaboratory comparison was conducted by the German Federal Office for Radiation Protection (BfS) and took place from 2018 to 2020. Participants were requested to measure radon in atmospheres of their own facilities according to their own procedures and requirements for metrological traceability. A measurement device with suitable properties was used to determine the comparison values. The results of the comparison showed that the radon activity concentrations that were determined by European calibration facilities complying with metrological traceability requirements were consistent with each other and had common mean values. The deviations from these values were normally distributed. The range of variation of the common mean value was a measure of the degree of agreement between the participants. For exposures above 1000 Bq/m3, the variation was about 4% for a level of confidence of approximately 95% (k=2). For lower exposure levels, the variation increased to about 6%.

This paper outlines the process of characterizing a new NORM material for proficiency testing made of quartz sand with significantly elevated levels of 226Ra obtained from the backflush of a drinking water treatment facility. Samples of the fully characterized NORM material were sent to European laboratories concerned with radioactivity measurements and environmental monitoring by gamma-ray spectrometry for proficiency testing. The paper discusses the results, specific requirements, problems and solutions that were found during the characterization process and the proficiency test.

In this paper spectral interference effects for selected gamma-emitting radionuclides of the natural decay series and 40K in selected NORM samples are studied. Recommendations for the choice of γ-lines and the consideration of possible spectral interferences are provided. Special attention is given to the radon tightness of the sample containers. A simple and sensitive method for the estimation of the 222Rn leakage of sample containers is introduced. The applied polystyrene sample containers show 222Rn leakages lower than 1%.

In the course of the Joint Danube Survey 3 (JDS3), coordinated by the International Commission for the Protection of the Danube River (ICPDR), laboratory ships travelled 2375km down the Danube River engaging in sampling, processing and on-board analyses during the summer of 2013. The results of the radiometric analysis of 90Sr, 137Cs and natural radionuclides in recent riverbed sediment are presented. The activity concentrations of 90Sr and 137Cs in Danube sediments have been found below 100Bq/kg.

In waterworks, 222 Rn can exhale in large amounts through open water surfaces and cause a significant dose contribution. Annual effective doses up to 56 mSv y −1 are documented in literature. This paper gives a literature review on studies associated with radon measurements in indoor air of waterworks − covering more than 800 waterworks in nine regions. Special attention is given to the assessment of the workers' effective dose, which can be done either on basis of the personal exposure or on basis of the local activity concentrations and the residence times. Especially at facilities with a water treatment, large diurnal variations depending on its operation mode were reported. The average 222 Rn concentrations may considerably differ during the time spent of the staff and do not allow to determine the correct annual effective doses. Personal detectors avoid this problem and do not require the survey of the residence times, while the determination of the local exposure allows for the identification of spots with high activity concentrations to set dose reduction measures.

In this work, a quick and simple low-level radionuclide metrology technique for the traceable measurement of Rn-222 activity concentration in drinking water using a 0.56l ionisation chamber operating in spectrometric pulse mode has been developed, tested, verified and applied to 16 water samples successfully. The impact of essential influencing factors on the result has been investigated, discussed and considered in the uncertainty budget of the measurement method. Finally, the new method has been assessed regarding the applicability on the EU Council Directive 2013/51. &nbsp

Main text An international comparison of activity per unit volume of 222Rn (EURAMET project N° 1475, registered in KCDB as supplementary comparison EURAMET.RI(II)-S8.Rn-222) was organised in 2019 within the framework of the European project MetroRADON. The LNE-LNHB is the pilot of the comparison. Samples of 222Rn gas provided by the LNE-LNHB were sent to the participants and were measured using various techniques. The reference value is the power moderated mean (PMM) (Pommé, 2013) of the seven submitted results. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

International audience; The 4πγ-counting technique is recognized as a powerful primary method for the standardization of radionuclides decaying with abundant gamma emissions. Based on the use of a gamma detector in quasi 4π-geometry, a detection efficiency close to 100% and a low uncertainty can be achieved thanks to the summing effect of subsequent gamma transitions. Uncertainties have to be assigned to the realistic modelling of the source–detector geometry with respect to dimensions, density and material composition, the calculation of the total counting efficiency of the detector for the various emitted radiation, and the effect of possible flaws in the decay scheme of a radionuclide on the calculated total efficiency. Other uncertainty factors pertain to typical metrological sources of uncertainty, such as weighing, nuclear counting with pulse pile-up and system dead-time effects, impurity corrections, decay corrections, timing and frequency, etc. In order to ensure good metrological practices at NMIs, the uncertainties particular to the method are discussed.

During the EMRP JRP MetroMETAL project a detector image of an aged HPGe gamma-ray detector was created for MC efficiency calculation. Using the nominal construction parameters of the detector, the simulation showed unacceptably high deviations from the assured activity values. This paper describes an optimisation of a virtual detector to obtain better results using limited resources and offers comparisons of efficiency values of point and voluminous sources calculated by LABSOCS® and PENELOPE 2011.

The radioactive noble gas radon is identified as the highest risk factor for lung cancer after smoking. The exhalation of radon from building materials can contribute to the radon indoor activity concentration. Therefore, the emanation of radon might be a crucial factor. It is defined as the release of radon from the solid soil matter into the pore space of the material. This article describes a new on-site measurement method for the emanation of radon from building materials at industrial sites. Therefore, a closed vessel with sample material and a passive radon detector inside is used to measure the integrated build-up-curve of the activity concentration. Additionally, a brief overview on existing radon emanation measurement methods is given.

Proceedings of the 7th International Conference on Radionuclide Metrology - Low Level Radioactivity Measurement Techniques (ICRM-LLRMT), 26 -30 September 2016, Seattle, USA; International audience; The results of the three years European Metrology Research Programme's (EMRP) joint research project 'Metrology for processing materials with high natural radioactivity' (MetroNORM) are presented. In this project, metrologically sound novel instruments and procedures for laboratory and in-situ NORM activity measurements have been developed. Additionally, standard reference materials and sources for traceable calibration and improved decay data of natural radionuclides have been established.

In this study the radon activity concentration of water samples from the so called "Thermenlinie" are measured using two different techniques: currents measured with an ionisation chamber setup developed by H. Friedmann are compared with results obtained using a commercially available AlphaGUARD. A fit to compensate for measurements made in non-equilibrium state is applied and the detection limit is estimated.

NORM emits many different gamma energies that have to be analysed by an expert. Alternatively, artificial neural networks (ANNs) can be used. These mathematical software tools can generalize “knowledge” gained from training datasets, applying it to new problems. No expert knowledge of gamma-ray spectrometry is needed by the end-user. In this work an ANN was created that is able to decide from the raw gamma-ray spectrum if the activity concentrations in a sample are above or below the exemption limits.

In this paper the assessment of natural radionuclides' activity concentration in building materials, calibration requirements and related indoor exposure dose models is presented. Particular attention is turned to specific improvements in low-level gamma-ray spectrometry to determine the activity concentration of necessary natural radionuclides in building materials with adequate measurement uncertainties. Different approaches for the modelling of the effective dose indoor due to external radiation resulted from natural radionuclides in building material and results of actual building material assessments are shown.

Reliable measurement of Naturally Occurring Radioactive Materials is of significance in order to comply with environmental regulations and for radiological protection purposes. This paper discusses the standardisation of three reference materials, namely sand, tuff and TiO2 to serve as quality control materials for traceability, method validation and instrument calibration. The sample preparation, material characterization via γ, α and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and the assignment of values for both the 4n (Thorium) and 4n+2 (Uranium) decay series are described.

The administration in many countries demands a classification of areas concerning their radon risk taking into account the requirements of the EU Basic Safety Standards. The wide variation of indoor radon concentrations in an area which is caused by different house construction, different living style and different geological situations introduces large uncertainties for any classification scheme. Therefore, it is of importance to estimate the size of the experimental coefficient of variation (relative standard deviation) of the parameter which is used to classify an area. Besides the time period of measurement it is the number of measurements which strongly influences this uncertainty and it is important to find a compromise between the economic possibilities and the needed confidence level. Some countries do not use pure measurement results for the classification of areas but use derived quantities, usually called radon potential, which should reduce the influence of house construction, living style etc. and should rather represent the geological situation of an area. Here, radon indoor measurements in nearly all homes in three municipalities and its conversion into a radon potential were used to determine the uncertainty of the mean radon potential of an area as a function of the number of investigated homes. It could be shown that the coefficient of variation scales like 1/√n with n the number of measured dwellings. The question how to deal with uncertainties when using a classification scheme for the radon risk is discussed and a general procedure is proposed.

The indoor radon concentration was measured in most houses in a couple of municipalities in Austria. At the same time the activity concentration of radium in soil, the soil gas radon concentration, the permeability of the ground and the ambient dose equivalent rate were also measured and the geological situations (geological units) were recorded too. From the indoor radon concentration and different house and living parameters a radon potential (Austrian radon potential) was derived which should represent the radon concentration in a standard room. Another radon potential (Neznal radon potential) was calculated from the soil gas radon concentration and the permeability. The aim of the investigation was to correlate all the different variables and to test if the use of surrogate data (e.g. geological information, ambient dose equivalent rate, etc.) can be used to judge the radon risk for an area without performing numerous indoor measurements.

Photon fluence spectra of the Seibersdorf Labor/BEV Picker 60Co therapy unit were calculated using two generally recognised Monte Carlo codes, PENELOPE-2006 and MCNP5. The complexity of the simulation model was increased in three steps (from a pure source capsule and a simplified model using rotational symmetry to a realistic model of the facility). Photon fluence spectra of both codes generally agree within their statistical standard uncertainties for the case of identical geometry set-up and particle transport parameter settings. Resulting total fluence values were about 0.3% higher for MCNP as compared to PENELOPE. The verification of the simulated photon fluence spectra was based upon depth–dose measurements in water performed with a PTW 31003 ionisation chamber and a thick-walled chamber type CC01. The depth–dose curve calculated with PENELOPE agreed with the curve obtained from measurements within 0.4% across the available depth region in the 30 cm × 30 cm × 30 cm water phantom. The comparison of measured and simulated beam quality indices (TPR20,10) revealed deviations of less than 0.2%.

A new method has been developed for determining the efficiency of large-area beta sources in anodized aluminum foils using transmission measurements. The method was applied to the efficiency measurement of a 90 Sr– 90 Y large-area reference source. Measurement results show that the method can provide efficiency values for 90 Sr– 90 Y reference sources with standard uncertainties smaller than 2.9%, which are far below the limit of 10% required by ISO 8769.

Dating of fluvial deposits is essential for a more quantitative understanding of landscape evolution and soil development in floodplain environments. We collected soil layers in defined depth intervals down to 60 cm along a substrate age gradient in a floodplain of the Danube River near Vienna, Austria. Depth profiles of fallout 137 Cs were used to assess short-term sedimentation, and optically stimulated luminescence (OSL) dating was used to attribute sediment deposits to time periods between the early last millennium BC and the 18th century AD. In the studied soils, the ratio of oxalate- to dithionite-extractable iron (Fe o /Fe d ), which indicates the degree of iron oxide crystallinity, progressively decreased from ratios greater than 0.5 to values less than 0.2 with increasing soil age and proved to be a reliable indicator of soil maturity. We linked the observed Fe o /Fe d ratios to the radiometric and OSL ages in a chronofunction, which allows to approximately date soil layers that lack an independent age control. The soil ages calculated with this chronofunction accurately reflected their geomorphological position, resulted in consistent age trends with depth, and highlighted the active morphodynamics of the studied floodplain. The chronofunction was further validated by dating a soil profile near the studied chronosequence that contained an archaeological find dated to the La Tene period (5th to 1st century BC).

In an intercomparison exercise, the Monte Carlo codes most commonly used in gamma-ray spectrometry today were compared with each other in order to gauge the differences between them in terms of typical applications. No reference was made to experimental data; instead, the aim was to confront the codes with each other, as they were applied to the calculation of full-energy-peak and total efficiencies. Surprising differences between the results of different codes were revealed.

The implementation of radon mitigation and precaution standards needs continuously scientific attendance and research networking on international level. Otherwise the radon issue could degrade easily to a simplified techno-economical exercise without sustainable results in public health. In this paper the radon investigations in Austria which have been carried out in the last 20 years and the applied methods and derived standards for mitigation and precaution at home and workplaces are discussed. Future strategies, scientific and social necessities to solve the radon problem are outlined comprehensively. The agreed and proposed future research objectives and cooperations in Austria that seem absolutely necessary are discussed in consideration of the medium-term perspective of the European radiation protection.

Substantial transformations of biogeochemical phosphorus (P) fractions can occur within a few hundreds of years under humid and tropical conditions; however, slower changes are expected under dry and temperate climate. The objective of this study was to infer P transformations over time by comparing suspended sediments in the Danube River to floodplain soils developed from such sediments over different time periods in the continental climate of Central Europe. We analyzed suspended sediments from 20 flood events between 1990 and 2006, and floodplain soils from seven sites along a chronosequence covering about 500 yrs. The studied flood sediments had similar characteristics over the 16-yr observation period. Total phosphorus (TP) averaged 732 mg kg−1, and biogeochemical fractionation yielded important primary mineral contributions (apatite phosphorus, AP, ~80% of TP). The TP concentrations of the floodplain soils were in the range of the Danube sediments and showed little variation along the chronosequence. However, the distribution of P among biogeochemical fractions changed considerably in less than 500 yrs of soil development. The youngest soils (

In 2012 and 2013 measurements of parameters relevant for a better prediction of the radon potential were carried out in Austria at 100 sites. The parameters were the (222)Rn activity concentration in soil gas, the soil's permeability, the ambient equivalent dose rate above the ground and the soil's massic activity by gamma spectrometry. The uncertainties of sampling and measurements are discussed as well as the correlations between these parameters.

Measurements of 137Cs fallout have been used in combination with a range of conversion models for the investigation of soil relocation mechanisms and sediment budgets in many countries for more than 20 yr. The objective of this paper is to develop a conversion model for quantifying soil redistribution, based on Chernobyl-derived 137Cs. The model is applicable on uncultivated as well as on cultivated sites, taking into account temporal changes in the 137Cs depth distribution pattern as well as tillage-induced 137Cs dilution effects. The main idea of the new model is the combination of a modified exponential model describing uncultivated soil with a Chapman distribution based model describing cultivated soil. The compound model subsequently allows a dynamic description of the Chernobyl derived 137Cs situation in the soil and its change, specifically migration and soil transport processes over the course of time. Using the suggested model at the sampling site in Pettenbach, in the Austrian province of Oberösterreich 137Cs depth distributions were simulated with a correlation coefficient of 0.97 compared with the measured 137Cs depth profile. The simulated rates of soil distribution at different positions at the sampling site were found to be between 27 and 60 Mg ha(-1) yr(-1). It was shown that the model can be used to describe the temporal changes of 137Cs depth distributions in cultivated as well as uncultivated soils. Additionally, the model allows to quantify soil redistribution in good correspondence with already existing models.

With the aim to predict the radon potential by geological data, radon soil gas measurements were made in a selected region in Styria, Austria. This region is characterised by mean indoor radon potentials of 130-280 Bq m(-3) and a high geological diversity. The distribution of the individual measuring sites was selected on the basis of geological aspects and the distribution of area settlements. In this work, the radon soil gas activity concentration and the soil permeability were measured at 100 sites, each with three single measurements. Furthermore, the local dose rate was determined and soil samples were taken at each site to determine the activity concentration of natural radionuclides. During two investigation periods, long-term soil gas radon measurements were made to study the time dependency of the radon activity concentration. All the results will be compared and investigated for correlation among each other to improve the prediction of areas with high radon potential.

In this chapter, a general review of radioecological research and exemplarily results of radioactivity measurements carried out in the Danube freshwater ecosystem in the last 30 years are presented. Sample collection techniques and sample preparation and radiometric measurement methods, developed and applied in radioecological studies of the Danube River, are shown comprehensively. Results of radiometric analysis of bottom sediment samples, collected continuously by sediment traps and additionally by grab sampling during Danube research cruises, are given and discussed. The main goal of the radioecological research studies is the protection of the environment to manage sustainable use and conservation of the Danube freshwater resource against harmful radioactive exposure.

The Austrian radon mitigation joint research project SARAH (supported by the Austrian Ministry of Economy and the Government of Upper Austria), a 2-year follow-up study of the Austrian National Radon Project (ONRAP), was started in 1996. The objectives of the research project were to find simple, cost-effective experimental methods for the characterisation of the radon situation in dwellings and to evaluate technically and economically the implementation of state of the art remedial actions for Austrian house types. After an intercomparison exercise of the assigned radon measuring instruments and detectors five houses were closely examined in regions with elevated radon levels in the federal state of Upper Austria. In this research work for the first time an extended Blower-Door method (which is conventionally used for determining the tightness of buildings) was successfully applied to radon diagnosis of buildings. In this paper the methods used for the radon diagnosis, the applied mitigation measures and the related technical and economical aspects are discussed. In conclusion of the results of this project a common strategy for solving the radon problem in Austria in the future is presented briefly.

In 2011 the joint research project Metrology for Radioactive Waste Management (MetroRWM). 11This joint research project is financially supported by the European Commission in the frame of the European Metrology Research Programme EMRP (www.emrponline.eu) undertaken by several EU Member States under the Article 169 initiative, JRP contract identifier EMRP ENV09 MetroRWM. of the European Metrology Research Programme (EMRP) started with a total duration of three years. Within this project, new metrological resources for the assessment of radioactive waste, including their calibration with new reference materials traceable to national standards will be developed.This paper gives a review on national, European and international strategies as basis for science-based metrological requirements in clearance and acceptance of radioactive waste. © 2013 Elsevier Ltd.

The aim of the Austrian Radon Project (ARP) is to investigate the 222Rn concentration in 0.3-0.5% of all Austrian dwellings to identify areas with elevated radon exposure. The survey is carried out using short-term and long-term integrating radon detectors covering a population of 2 800 000 persons so far. The homes were randomly selected from the telephone directory. The radon concentration distribution showed a log-normal shape. County-means between 60 and 330 Bq/m3 were found. A radon potential was introduced to deduce a geological risk from the data taken under different circumstances in different types of houses. This radon potential was defined as the annual mean radon concentration in a standard dwelling and is computed by normalizing the measured radon data to this standard dwelling.

In continuation of earlier radio-ecological studies, the results of specific investigations on the behavior of natural radionuclides ( 238 U, 226 Ra, 210 Pb, 40 K) in the freshwater environment of the Austrian part of the Danube River are presented. The investigations and interpretations of the results are carried out with regard to the partitioning of radionuclides in fresh water between the particulate and soluble phases. The underlying work is a mixture of radiometric analysis of in situ -samples of water, suspended matter and sediments of the fresh water environment of the Danube River, and grain size analysis. The affinities of the partitioning of the observed natural radionuclides to the artificial radionuclide 137 Cs are shown. Specific attention is paid to the influence of non-radiometric parameters, such as, hydrological conditions (i.e., flow rate), solid particle concentration, and grain size distribution of suspended matter on the radionuclide partitioning and the dynamics of water/solid matter interactions. The results of this work can be used as a basis for investigations on special problems of fresh water radioecology (i.e., a more realistic parameter assessment for radio ecological fresh water models) in Alpine regions and for investigations of general environmental processes (i.e., distribution of atmospheric pollutants in a large river fresh water ecosystem; land erosion processes).

A comprehensive study with the aim to evaluate the risks due to radiation exposure for workers in water supply is conducted in 21 Austrian waterworks. The development of standard methods for the assessment of occupational exposure of water work staff is a part of this study. Preliminary results of this study show a wide range of Rn-222 activity concentration in waterworks with values from (28±10) Bq/m 3 to (38,000±4000) Bq/m 3 . Also seasonal variations of the Rn-222 activity concentration could be observed.

Soil gas radon measurements are carried out in a pilot study in three municipalities in Upper Austria. The selected municipalities are characterised by a high radon potential. Sixty measuring sites--well distributed over the region and over the different geological areas--were selected. Additionally, the permeability of the soil was determined where the soil gas samples were taken and at various sites where soil samples were analysed by gamma spectrometry. Long-term soil-gas radon concentration measurements are carried out at several sites to study the long-term behaviour of radon activity concentration in soil, the influence of meteorological parameters and seasonal variations. The final goal of the project is to correlate the collected data with geological data and indoor radon concentration. First results of this ongoing study are presented and discussed.

The graphite calorimeter of the Federal Office of Metrology and Surveying (BEV-Bundesamt fur Eich- und Vermessungswesen) was established in the 1980s as the primary standard for the absorbed dose to water for (60)Co gamma ray beams. To maintain the primary standard at an international level the graphite calorimeter and its corresponding components had to undergo a refurbishment and modernisation process. The correction factors of the graphite calorimeter were re-evaluated with Monte Carlo and experimental methods to obtain improved values. These are the correction for the effect of the gaps (1.0061), the scaling correction (0.9998), the correction for the difference in air attenuation (0.9971) and the corrections for the effective measurement depths in the graphite phantom for the graphite calorimeter (0.9886) and the CC01-105 ionisation chamber (0.9913). Consequently, it was necessary to change the reference value for the absorbed dose rate to water of the (60)Co teletherapy unit used for the calibration of secondary standard dosemeters.

Photon energy spectra of Varian Clinac 2100C and 2300C/D treatment heads were calculated with PENELOPE-2006, using simplified Monte Carlo models. These spectra constitute the basis of beam models used for the calculation of correction factors required for the Austrian absorbed dose to water primary standard. To validate the models, simulated depth dose curves in water and calculated radiation quality factors (TPR(20,10)) were compared with ionization chamber measurements. In addition the results are discussed in context with detailed Monte Carlo studies from the literature in reference to mean spectral photon energy and degree of equivalence between simulated and calculated percentage-depth-dose curves. Mean absolute deviations between measured and simulated depth dose curves smaller than 2.0% were found. The differences between simulation and measurement of TPR(20,10) were smaller than 2.6%. This shows the usefulness of the simplified beam models in applications since their dependence on energy spectra and radiation quality is small in comparison to its energy range.

According to the European Drinking Water Directive 98/83/EC a pilot project for the assessment of the radiological situation of drinking water was realized in Austria. About 350 drinking water samples were taken in Upper Austria and analyzed for several natural radionuclides by different measuring techniques. Techniques are tested and compared and an overview of the results is given. Additionally, parameters for drinking water assessment have been worked out to standardize monitoring programs and simplify experts’ activities.

Sampling techniques and radiometric methods, developed and applied in a comprehensive radioecological study of the Danube River are presented. 1 Results and radiometric data of sediment samples, collected by sediment traps in Austria and additionally by grab sampling in the Danube during research cruises between Germany and the delta (Black sea) are shown and discussed. Goal of the investigation is the protection of public and environment, especially the sustainable use and conservation of human freshwater resources against harmful radioactive exposure.

Soil gas radon measurements complement indispensable and well-established radon indoor measurements in Austria. Radon in soil gas is a result of geochemical conditions as well as of geology, mineralogy, geophysics and meteorology. Therefore, geological factors can help to predict potential indoor radon concentrations via soil gas. Soil gas radon measurements in well-defined geological units give an estimate of local and regional radon hazards and build the basis for radon risk maps, which could be used for land-use planning and urban development. The creation of maps makes an important contribution to health care. For this purpose, several research projects were carried out in Austria. On the one hand, a study was already conducted in Lower Austria to determine the influence of meteorological and soil physical parameters on radon concentrations in soil gas and to evaluate soil gas radon concentrations with a radon emanation and migration model. On the other hand, radon measurements on different geomorphologic formations in the Austrian Alps, which are potential settlement areas, are of special interest.

Over the past 15 years scientific research and application-oriented research were carried out in Austria to resolve the radon problem. In this paper, the strategy and progression of radon research in Austria and experience gained by practical implementation of the main findings are shown and discussed comprehensively. The overview includes the results of the national radon survey, radon mitigation and precaution studies, indoor-air studies at kindergartens and schools, soil-gas radon research, and the establishment of national radon precaution and mitigation standards.

For the first time, a comparison of radon activity concentration in air has been performed within the scope of Euromet. In the project 657, 'Comparison of calibration facilities for the radon activity concentration,' 12 participants from 9 countries compared different radon reference atmospheres at 1, 3 and 10 kBq m-3 via a transfer standard. The comparison was listed as BIPM supplementary comparison EUROMET.RI(II)-S1. The results of most participants are correlated due to common traceability to one single radon gas standard producer. This makes a careful correlation analysis necessary to achieve an appropriate comparison reference value. The results of the comparison as well as the complex analysis of the correlated set of data is presented and discussed. © 2006 Elsevier Ltd. All rights reserved.

Publisher Summary International intercalibration and intercomparison exercises are used as an important tool to provide confidence in the capability of national metrology institutes and calibration laboratories. The quality systems of national institutes provide the basis for running intercomparisons, in this case, in the field of the radon activity concentration in air. Interchange of an electronic radon measuring instrument (intercomparison device) that demonstrated ruggedness during shipping in the past, was considered a convenient means for a relative comparison of radon reference atmospheres. Practical problems of measuring technique led to a restriction to the quantity of the radon activity concentration in the case of most radiation protection measurements. This leads to higher uncertainties in exposure and dose calculations, as well as in the risk estimations of epidemiology. Improvements in metrology and the extension of calibration capabilities worldwide to radon progeny measurement are therefore be of great practical importance.

Prior to 2002, no comparisons of radon activity concentration had been performed within the scope of the EUROMET. The comparison presented here fulfils the need to provide confidence in the capability of national metrology institutes and calibration laboratories to measure radon activity concentration in air. This has been achieved by the measurement of radon reference atmospheres using an electronic, radon measuring instrument as the transfer comparison device (CD). Each of the twelve institutes, from nine countries, calibrated the CD using standard calibration procedures according to their quality system, at three different activity concentrations: 1 kBq/m3, 3 kBq/m 3 and 10 kBq/m3. For each activity concentration, a comparison reference value and its uncertainty have been derived. From these the degrees of equivalence have been calculated and are presented graphically and in the form of matrices. All the results are consistent within the assigned uncertainties. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by EUROMET, according to the provisions of the Mutual Recognition Arrangement (MRA).

Since 2009, three national metrology institutes (NMI) have submitted three samples of known activity of 133Ba to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ba-133, to update their earlier result dating more than 15 years ago. The values of the activity submitted were between about 2 MBq and 3 MBq. There are now nine results in the BIPM.RI(II)-K1.Ba-133 comparison. The degrees of equivalence between each equivalent activity measured in the SIR and the key comparison reference value (KCRV) have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Radionuclides present in the Danube catchment area were used to investigate the behaviour of radionuclides in the Austrian part of the Danube river. Sampling of different compartments such as water, suspended matter and fine sediment was carried out from 1989 to 1992; on some sites since 1987. Measurements of some radionuclides of these complementing samples, which were taken at different locations on the Danube river in Austria on a monthly basis lead to well proved results. Investigations were devoted to the influence of high-water flooding on the behaviour of the radionuclides in the system. The results were taken as a basis for evaluating environmental parameters, modelling and dose assessment to give a uniform view of the radioecology in the Austrian part of the Danube river.

As a part of a special monitoring program, evaluation of the measurements for deriving in situ K d factors was carried out. Radionuclides present in the Danube catchment area were used to investigate the behaviour of radionuclides in the Austrian part of the Danube river. Measurements of some radionuclides of different components of sediments representing complementing samples, which were taken at different locations at the Danube river in Austria on a monthly basis lead to well proved results. Some investigations were devoted to the influence of unusual hydrological conditions as high-water flooding to the behaviour of radionuclides in the system. The results are reported including uncertainties and influencing parameters. The results of these investigations are discussed in relation to default values and for their importance in environmental modelling and dose assessment.