Preparation and certification of 243Am spike reference material: IRMM-0243 : Certified reference material for the amount content of 243Am and n(241Am)7n(243Am) isotope amount ratio

This report describes the preparation and certification of IRMM-0243, a 243Am spike reference material. It is certified for the amount content of 243Am and the isotope amount ratios of n(241Am)/n(243Am) and n(242mAm)/n(243Am). Furthermore, the material is certified for the amount contents of 241Am and total Am, the mass fractions of 243Am, 241Am and total Am, the isotope amount and mass fractions (e.g. isotopic composition) and the molar mass of Am. The material was produced in compliance with ISO/IEC 17034:2016 and certified in accordance with ISO Guide 35:2006. The material was prepared by dilution of an americium starting solution in nitric acid and dispensing of the solution into glass ampoules. In total 587 units were produced. Between-unit homogeneity was quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2006. The characterisation of the amount content of 243Am was performed by Isotope Dilution Mass Spectrometry (IDMS) using a 241Am spike, produced from highly enriched 241Pu material. The isotope amount ratios of n(241Am)/n(243Am) and n(242mAm)/n(243Am) were measured by Thermal Ionisation Mass Spectrometry (TIMS). The certified values were verified by alpha particle spectrometry, alpha particle counting at a defined solid angle (DSA) and high-resolution gamma-ray spectrometry as independent verification methods. The uncertainties of the certified values were estimated in compliance with the Guide to the Expression of Uncertainty in Measurement (GUM) [ ] and include uncertainties related to possible inhomogeneity, instability and characterisation. The main purpose of this material is for use as a spike isotopic reference material for the quantification of americium by IDMS in unknown samples. A unit of IRMM-0243 consists of a glass ampoule with a screw cap containing about 3.5 mL nitric acid solution (c = 1 mol/L) with an americium mass fraction of about 1.5 μg/g solution. The material is a true solution; therefore there is no recommended minimum sample intake to be taken into account.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

Ionising radiation metrology for the metallurgical industry

Every year millions tons of steel are produced worldwide from recycled scrap loads. Although the detection systems in the steelworks prevent most orphan radioactive sources from entering the furnace, there is still the possibility of accidentally melting a radioactive source. The MetroMetal project, carried out in the frame of the European Metrology Research Programme (EMRP), addresses this problem by studying the existing measurement systems, developing sets of reference sources in various matrices (cast steel, slag, fume dust) and proposing new detection instruments. This paper presents the key lines of the project and describes the preparation of radioactive sources as well as the intercomparison exercises used to test the calibration and correction methods proposed within the project.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Interlaboratory comparison on 137Cs activity concentration in fume dust

Proceeding of the 9th International Topical Meeting on Industrial Radiation and Radioisotope Measurement Applications, 6-7 July 2014, Valencia, Spain.; International audience; A comparison was conducted, between 11 European National Metrology Institutes and EC-JRC, on measurement of Cs-137 activity concentration in fume dust. As test material an activity standard produced from real contaminated fume dust was used. The standard material consisted of 13 cylindrical samples of compressed fume dust. The material contained Cs-137 and Co-60 of reference activity concentrations of (9.72 +/- 0.10) Bq/g and (0.450 +/- 0.018) Bq/g, respectively, for the reference date of 1 June 2013, determined using the comparison results. The organization and results of the intercomparison, as well as the process of obtaining reliable reference values are presented

60Co in Cast Steel Matrix: a European Interlaboratory Comparison for the Characterisation of New Activity Standards for Calibration of Gamma-ray Spectrometers in Metallurgy

International audience; Two series of activity standards of Co-60 in cast steel matrix, developed for the calibration of gamma-ray spectrometry systems in the metallurgical sector, were characterised using a European interlaboratory comparison among twelve National Metrology Institutes and one international organisation. The first standard, consisting of 14 disc shaped samples, was cast from steel contaminated during production ("originally"), and the second, consisting of 15 similar discs, from artificially-contaminated ("spiked") steel. The reference activity concentrations of Co-60 in the cast steel standards were (1.077 +/- 0.019) Bq g(-1) on 1 January 2013 12h00 UT and (1.483 +/- 0.022) Bq g(-1) on 1 June 2013 12h00 UT, respectively

Characterisation of an ultra low-background point contact HPGe well-detector for an underground laboratory

Since a few years there are well-type HPGe-detectors with a small, point-like, anode contacts available commercially. This paper describes the characterisation of the first ultra low-background, so-called, SAGe™ well detector with regards to resolution and background performance. Inside a passive lead/copper shield in the underground laboratory HADES a background count rate of 690 ± 6 d−1 (268 ± 3 d−1 per kg Ge) was recorded 19 months after taking it underground.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

A gamma-ray spectrometry analysis software environment

At the JRC-Geel's RadioNuclide Metrology sector, a Monte Carlo code based on EGSnrc, and a general purpose calculation sheet implemented in Microsoft Excel®, have been developed to make the quantitative gamma-ray spectrometry analysis of samples simpler and more robust. The further aim is that the software can be used by non-experts in gamma-ray spectrometry e.g. external researchers using JRC-Geel’s facilities through the EUFRAT transnational access scheme. This paper presents the developed Monte Carlo software and the functionality included in the calculation sheet.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

Measurement of anthropogenic radionuclides in post-Fukushima Pacific sea water samples

Following the accident at the Dai-ichi Fukushima nuclear power plant in 2011, a vast number of Pacifîc sea water samples from many locations far from Fukushima have been collected by Japanese investigators. Due to dilution, the activities of radionuclides from North Pacifîc sea water samples are very low, which calls for extraordinary measures when being measured. This paper focusses on the metrological aspects of the gamma-ray spectrometry measurements performed on such samples in two underground laboratories; at HADES (by JRC-IRMM in Belgium), and at Ogoya (by Kanazawa University in Japan). Due to many samples and long measurement times, all available HPGe-detectors needed to be employed. In addition to single coaxial detectors, this involved multi-detector systems and well-detectors. Optimization of detection limits for different radionuclides and detectors were performed using Monte Carlo simulations.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Characterization of 226Ra activity in low-level slag reference standards

Within the EURAMET European Metrology Research Programme project IND04 named MetroMetal, several different reference standards have been developed for the metallurgical industry. This paper describes the characterisation of low-levels of 226Ra in samples of slag. The activity was determined through spiking with a known amount of solution containing 226Ra to a previously characterised slag material. The measurements were performed at both 225 m underground and aboveground. The total (spiked + natural) massic activity of 226Ra obtained from the gamma-ray spectrometry measurements was (126.3 ± 5.6) Bq/kg. A comparison of the different measurements and studies of the distribution of radon-daughters in the samples is presented.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Tracing radioactivity from Fukushima in the Northern Pacific Ocean

Following the accident a the Fukushima Daiichi nuclear power plant, a campaign of sampling and measuring anthropogenic radionuclides in North Pacific seawater was set up. The main aim was to study natural processes using these radionuclides as tracers. Because of dilution, the activities of anthropogenic radionuclides at long range were very low and their measurement required advanced pre-concentration techniques and underground gamma-ray spectrometry. Data and metrological aspects of the measurements using HPGe-detectors are presented and discussed.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard