Background: Inductively coupled plasma mass spectrometry (ICP-MS) techniques have been widely used for analysis of long-lived environmental radionuclides. In this paper, we present an optimization of the sector field (SF)-ICP-MS technique for the analysis of 226 Ra in groundwater samples using a method of pre-concentration of radium in water samples. Methods: The separation protocol and a sequential application of ion exchange and extraction chromatography have been optimized, and related polyatomic interferences and matrix effects affecting the
Rare events search experiments, like those dedicated to the direct evidence of dark matter or neutrinoless double beta decay, are among the most exciting challenges of modern physics. The sensitivity of such experiments is driven by the background, which depends substantially on the radiopurity of the materials used for the experimental apparatus. Cutting edge measurement techniques are needed for a fast, sensitive and efficient screening of these materials and the certification of their production. Trace element measurements of high sensitivity and quick execution are mandatory also in other fields like tracing the geographical origin of food, temporal and geographical assignment of cultural heritage or monitoring environmental radioactivity. This work is an overview of the inorganic mass spectrometry facility available at Gran Sasso National Laboratory (LNGS) for radiopure material screening and is especially focused on its ICP-MS instrumentation. Analytical methods developed to achieve lowest detection limits in different types of matrix, like metals, polymers, crystals and composite materials, are also indicated. Detection limits of [Formula: see text] for [Formula: see text], [Formula: see text] for U and Th and [Formula: see text] for K are attained through dedicated operation conditions of the instrumentation. Details are given on the results obtained for different experiments ongoing or under construction at LNGS.
Tritium (3H) in Earth’s precipitation is vigilantly monitored since historical nuclear bomb tests because of radiological protection considerations and its invaluable role as a tracer of the global water cycle in quantifying surface, groundwater, and oceanic fluxes. For hydrological applications, accurate knowledge of 3H in contemporary local precipitation is prerequisite for dating of critical zone water and calibrating hydrogeologic transport and groundwater protection models. However, local tritium input in precipitation is hard to constrain due to few 3H observation sites. We present new high-spatial resolution global prediction maps of multi-year mean 3H in contemporary “post-bomb” (2008–2018) precipitation by using a robust regression model based on environmental and geospatial covariates. The model accurately predicted the mean annual 3H in precipitation, which allowed us to produce global 3H input maps for applications in hydrological and climate modelling. The spatial patterns revealed natural 3H in contemporary precipitation sufficient for practical hydrological applications (1–25 TU) but variable across continental regions and higher latitudes due to cumulative influences of cyclical neutron fluxes, stratospheric inputs, and distance from tropospheric moisture sources. The new 3H maps provide a foundational resource for improved calibration of groundwater flow models and critical zone vulnerability assessment and provides an operational baseline for quantifying the potential impact of future anthropogenic nuclear activities and hydroclimatic changes.
Tritium ( 3 H) is an important hydrological tracer commonly used for over 60 years to evaluate water residence times and water dynamics in shallow/recent groundwaters, streams, lakes and the ocean. We tested the analytical performance of 78 international laboratories engaged in low-level 3 H assays for water age dating and monitoring of environmental waters.
METHODS:Seven test waters were distributed by the IAEA to 78 international tritium laboratories. Set 1 included a tritium-free groundwater plus three ultra-low 3 H samples (0.5-7 TU) for meeting groundwater dating specifications. Set 2 contained three higher 3 H-content samples (40-500 TU) suitable for testing of environmental monitoring laboratories.
RESULTS:Seventy of the laboratories used liquid scintillation counting with or without electrolytic enrichment, seven utilized 3 He accumulation and mass-spectrometry, and one used gas-proportional counting. Only ~50 % of laboratories demonstrated the ability to generate accurate 3 H data that was precise enough for water age dating purposes.CONCLUSIONS: TRIC2018 helped identify recurrent weaknesses and potential solutions.Strategies for performance improvement of 3 H laboratories include: a) improved quantification of 3 H detection limits and analytical uncertainty, b) stricter quality control practices in routine operations along with care and recalibration of 3 H standards traceable to primary NIST standards, c) annual assessment of enrichment factors and instrumental performance, and d) for water age dating purposes the use of electrolytic enrichment systems having the highest possible 3 H enrichment factors (e.g. > 50x).
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