Earth is constantly bombarded with extraterrestrial dust containing invaluable information about extraterrestrial processes, such as structure formation by stellar explosions or nucleosynthesis, which could be traced back by long-lived radionuclides. Here, we report the very first detection of a recent ^{60}Fe influx onto Earth by analyzing 500 kg of snow from Antarctica by accelerator mass spectrometry. By the measurement of the cosmogenically produced radionuclide ^{53}Mn, an atomic ratio of ^{60}Fe/^{53}Mn=0.017 was found, significantly above cosmogenic production. After elimination of possible terrestrial sources, such as global fallout, the excess of ^{60}Fe could only be attributed to interstellar ^{60}Fe which might originate from the solar neighborhood.

The AMS setup at the Maier-Leibnitz-Laboratory (MLL) in Garching features a 14 MV tandem accelerator and two dedicated beam lines for high-sensitivity measurements of isotopes in all mass ranges. Especially in the medium mass range (70 < A < 120), AMS sensitivity is often limited by isobaric and isotopic background with only small relative difference in Z and/or A. Here, we present recent developments and upgrades at the MLL with special focus on improved sensitivity and new techniques for challenging AMS isotopes such as Zr-93 and Tc-99. Upgrades of the measurement setup as well as radiopurity studies for AMS samples, which could be altered by atmospheric neutrons during transportation by aircraft, are discussed.

After the Fukushima accident, large amounts of radionuclides were discharged to the atmosphere. Some of them travelled long distances and were detected in places as far from Japan as Spain a few days after the accident. One of these radionuclides was 131I. Its isotope 129I (T1/2 = 15.7 × 106 years) was also expected to follow the same pathway. In this work, we present the results for the 129I concentration in the same atmospheric samples from Seville (Spain) where 131I activity was measured in 2011 by Baeza et al. (2012). 129I concentrations in aerosol and gaseous samples showed concentrations in the order of 104 and 105 atoms/m3, typically higher in the gaseous form with respect to the aerosol form. Also 129I in rainwater was measured, showing concentrations in the order of 108 atoms/L. The results show a very good agreement with the 131I profile, showing that, if background from other sources is not relevant, it is possible to estimate the impact of similar events years after them thanks to the sensitivity of techniques like Accelerator Mass Spectrometry.

Calorimetric low temperature detectors (CLTD’s) for heavy-ion detection have been combined with the LOHENGRIN recoil separator at the ILL Grenoble for the determination of nuclear charge distributions of fission fragments produced by thermal neutron-induced fission of \(^{235}\)U. The LOHENGRIN spectrometer separates fission fragments according to their mass-to-ionic-charge ratio and their kinetic energy, but has no selectivity with respect to nuclear charges Z. For the separation of the nuclear charges, one can exploit the nuclear charge-dependent energy loss of the fragments passing through an energy degrader foil (absorber method). This separation requires detector systems with high energy resolution and negligible pulse height defect, as well as degrader foils which are optimized with respect to thickness, homogeneity, and energy loss straggling. In the present, contribution results of test measurements at the Maier Leibnitz tandem accelerator facility in Munich with \(^{109}\)Ag and \(^{127}\)I beams with the aim to determine the most suitable degrader material, as well as measurements at the Institut Laue–Langevin will be presented. These include a systematic study of the quality of Z-separation of fission fragments in the mass range \(82\le A \le 132\) and a systematic measurement of \(^{92}\)Rb fission yields, as well as investigations of fission yields toward the symmetry region.

A dying massive star ends in a supernova explosion ejecting a large fraction of its mass into the interstellar medium. If this happens nearby, part of the ejecta might end on Solar System bodies and, in fact, radioactive ^{60}Fe has been detected on the Pacific ocean floor in about 2 Ma old layers. Here, we report on the detection of this isotope also in lunar samples, originating presumably from the same event. The concentration of the cosmic ray produced isotope ^{53}Mn, measured in the same samples, proves the supernova origin of the ^{60}Fe. From the ^{60}Fe concentrations found we deduce a reliable value for the local interstellar fluence in the range of 1×10^{8}  at/cm^{2}. Thus, we obtain constraints on the recent and nearby supernova(e).

A dying massive star ends in a supernova explosion ejecting a large fraction of its mass into the interstellar medium. If this happens nearby, part of the ejecta might end on Solar System bodies and, in fact, radioactive Fe-60 has been detected on the Pacific ocean floor in about 2 Ma old layers. Here, we report on the detection of this isotope also in lunar samples, originating presumably from the same event. The concentration of the cosmic ray produced isotope Mn-53, measured in the same samples, proves the supernova origin of the Fe-60. From the Fe-60 concentrations found we deduce a reliable value for the local interstellar fluence in the range of 1 x 10(8) at/cm(2). Thus, we obtain constraints on the recent and nearby supernova(e).

Interplanetary Dust Particles (IDPs) are small grains, generally less than a few hundred micrometers in size. Their main source is the Asteroid Belt, located at 3AU from the Sun, between Mars and Jupiter. During their flight from the Asteroid Belt to the Earth they are irradiated by galactic and solar cosmic rays (GCR and SCR), thus radionuclides are formed, like 41Ca and 53Mn. Therefore, 41Ca (T1/2=1.03×105yr) can be used as a key tracer to determine the accretion rate of IDPs onto the Earth because there are no significant terrestrial sources for this radionuclide. The first step of this study consisted to calculate the production rate of 41Ca in IDPs accreted by the Earth during their travel from the Asteroid Belt. This production rate, used in accordance with the 41Ca/40Ca ratios that will be measured in snow samples from the Antarctica will be used to calculate the amount of extraterrestrial material accreted by the Earth per year. There challenges for this project are, at first, the much longer time for the flight needed by the IDPs to travel from the Asteroid Belt to the Earth in comparison with the 41Ca half-life yields an early saturation for the 41Ca/40Ca ratio, and second, the importance of selecting the correct sampling site to avoid a high influx of natural 40Ca, preventing dilution of the 41Ca/40Ca ratio, the quantity measured by AMS.

A chemical separation procedure for plutonium (Pu) and neptunium (Np) was developed using extraction chromatography, mass spectrometry and radiometric analysis to determine their concentrations and isotopic ratios in sea water. 241Am, which causes isobaric background to 241Pu in mass spectrometric measurements, was successfully separated from the Pu fraction by this method. Water samples which were spiked with 242Pu and 237Np or 239Np, respectively, were used for chemical yield determination. The chemical yields of Pu and Np, which were determined by alpha and gamma spectrometry at the Radiochemie München (RCM), of more than 85% were obtained. The developed method was applied to analyze the concentration of Pu and Np in the certified reference material, IAEA-443, by Accelerator Mass Spectrometry (AMS) at the Maier–Leibnitz-Laboratory (MLL) to check the applicability of the method to sea water samples. The concentrations of 240Pu, 241Pu and 237Np obtained in this study are in agreement with the certified and literature values within the uncertainties. Due to strong isotopic interference of 239Pu with 238U, it was not possible to analyze the concentration of 239Pu. Some modifications of the chemical separation method to suppress the uranium (U) fraction are under consideration. This method can be used for the analysis of Pu and Np in Pacific Ocean water samples collected after the Fukushima accident.

The sensitivity of rare event physics experiments like neutrino or direct dark matter detection crucially depends on the background level. A significant background contribution originates from the primordial actinides thorium (Th) and uranium (U) and the progenies of their decay chains. The applicability of ultra-sensitive Accelerator Mass Spectrometry (AMS) for the direct detection of Th and U impurities in three copper samples is evaluated. Although AMS has been proven to reach outstanding sensitivities for long-lived isotopes, this technique has only very rarely been used to detect ultra low concentrations of primordial actinides. Here it is utilized for the first time to detect primordial Th and U in ultra pure copper serving as shielding material in low level detectors. The lowest concentrations achieved were (1.5±0.6)·10-11g/g for Th and (8±4)·10-14g/g for U which corresponds to (59±24) and (1.0±0.5)μBq/kg, respectively.

Cosmogenic He, Ne, and Ar as well as the radionuclides Be-10, Al-26, Cl-36, Ca-41, Mn-53, and Fe-60 have been determined on samples from the Gebel Kamil ungrouped Ni-rich iron meteorite by noble gas mass spectrometry and accelerator mass spectrometry (AMS), respectively. The meteorite is associated with the Kamil crater in southern Egypt, which is about 45 m in diameter. Samples originate from an individual large fragment ("Individual") as well as from shrapnel. Concentrations of all cosmogenic nuclides-stable and radioactive-are lower by a factor 3-4 in the shrapnel samples than in the Individual. Assuming negligible Cl-36 decay during terrestrial residence (indicated by the young crater age <5000 years; Folco et al. 2011), data are consistent with a simple exposure history and a Cl-36-Ar-36 cosmic ray exposure age (CRE) of approximately (366 +/- 18) Ma (systematic errors not included). Both noble gases and radionuclides point to a pre-atmospheric radius >85 cm, i.e., a pre-atmospheric mass >20 tons, with a preferred radius of 115-120 cm (50-60 tons). The analyzed samples came from a depth of approximately 20 cm (Individual) and approximately 50-80 cm (shrapnel). The size of the Gebel Kamil meteoroid determined in this work is close to estimates based on impact cratering models combined with expectations for ablation during passage through the atmosphere (Folco et al. 2010, 2011).

The measurement of trace element concentration in aerosols is of interest for environmental studies and for human health assessment. The temporal variability of total suspended particles (TSP) and its elemental composition in Seville, in SW Spain, is of particular complexity since Atlantic air masses and Saharan Dust Intrusions (SDI) overlap to local natural and anthropogenic sources. This paper is aimed to study the temporal evolution (in a monthly basis) of the concentrations of 25 trace elements, determined by ICP-MS, in high-volume air filter samples from Seville, covering a two-year period: 2001–2002. The mean TSP value for this period was 79.7μgm−3 and showed peak values in August 2001 and June 2002, likely related to SDI. Enrichment factors (EF) for Se, Sb and Zn and Pb were above 100, which revealed their anthropogenic sources. The comparison among EF from Seville and Huelva, a highly industrialized city nearby Seville, showed higher levels of anthropogenic elements there than in Seville. Simulations of the transport/dispersion of pollutants starting in Huelva confirm that air pollutants can reach Seville in the course of around 6hours although they do not contribute significantly to the levels found in this city. A significant temporal correlation was found between elements which have a common source, being crustal (Al, Ti, Be, Co, Cs, Fe, Cr, Mn, U, Sr and Th) or anthropogenic sources (Zn, Pb, Cd). The temporal variations of those crustal elements are similar and related with the TSP levels for both years, with the clearly visible peaks probably related with the Saharan dust intrusion.

Measurements of 129I carried out on sea ice samples collected in the central Arctic Ocean in 2007 revealed relatively high levels in the range of 100–1400 × 107 at L−1 that are comparable to levels measured in the surface mixed layer of the ocean at the same time. The 129I/127I ratio in sea ice is much greater than that in the underlying water, indicating that the 129I inventory in sea ice cannot be supported by direct uptake from seawater or by iodine volatilization from proximal (nearby) oceanic regimes. Instead, it is proposed that most of the 129I inventory in the sea ice is derived from direct atmospheric transport from European nuclear fuel reprocessing plants at Sellafield and Cap La Hague. This hypothesis is supported by back trajectory simulations indicating that volume elements of air originating in the Sellafield/La Hague regions would have been present at arctic sampling stations coincident with sampling collection.

129I is a very long-lived radionuclide (T1/2 = 15.7 × 106 years) that is present in the environment because of natural and anthropogenic sources. Compared to the pre-nuclear era, large amounts of 129I have been released to the marine environment, especially as liquid and gaseous discharges from two European reprocessing facilities located at Sellafield (England) and La Hague (France). The marine environment, i.e., the oceans, is the major source of iodine. Brown seaweed accumulates iodine at high levels up to 1.0% of dry weigh, and therefore they are ideal bioindicators for studying levels of 129I. In this work, 129I concentrations have been determined in seaweed Fucus vesiculosus and seawater collected in the Kattegat and Skagerrak areas in July 2007. The resulting data were evaluated in terms of 129I concentrations and 129I/137Cs ratios. 129I concentrations were found to be in the order of (44–575) × 109 atoms g−1 in seaweed and (5.4–51) × 109 atoms g−1 in seawater, with an enhancement in the Skagerrak area in comparison to the Kattegat area. Iodine-129 concentrations in both seaweed and seawater were used to determine the concentration factor of iodine in brown seaweed F. vesiculosus. The high levels of 129I and 129I/137Cs ratios in the Skagerrak area and their gradually decreasing trend to the Kattegat indicates that the most important contribution to the 129I inventory in those areas comes from Sellafield and La Hague reprocessing plants.

Large amounts of iodine-129 were, and still are, released into the environment from nuclear facilities, in particular from two reprocessing facilities located on the east coast of the North Atlantic Ocean (Sellafield and La Hague). The main transport path of the releases from the two facilities is through the North Atlantic Current (NAC) and subsequently the Norwegian Coastal Current (NCC) to the Arctic Ocean. Iceland lies on the Scotland–Greenland ridge, which separates the Atlantic and Arctic oceans. 129I data available in that area are scarce despite their importance in modeling 129I dispersion through the North Atlantic and Arctic Oceans. For this reason, we have determined the 129I/127I ratio in seawater samples by means of Accelerator Mass Spectrometry (AMS) from three locations at the Iceland and Irminger Basins at different depths (from surface to 1000m) in order to study the transport pathways of the anthropogenic releases to the waters. The measured 129I/127I ratios, compared to the pre-anthropogenic 129I/127I value, show the strong influence of the artificial 129I discharges in the North Atlantic waters.

Background: Microdosing is a technique for studying the behavior of compounds in vivo at 1/100th of the dose of a test substance calculated, based on animal data, to yield a pharmacologic effect. In microdosing, use is made of accelerator MS (AMS). In this study, we investigated whether 129I-labeling of proteins with subsequent AMS measurements is a suitable method to perform microdose studies with therapeutic proteins. We used erythropoietin (EPO) as a case study. Results: In an animal study with 129I-labeled EPO in Han-Wistar rats, an increase of 129I-EPO is observed after dose administration. The half-life was found to be 2 and 5.5 h for two different EPOs. These results are in accordance with expected values. Conclusion: Although further research is required, 129I-labeling of proteins seems a feasible method for AMS microdose studies with peptide and protein drugs, such as biosimilars.

In this paper we present a MATLAB code built to model the transport of a charged particle beam through the Accelerator Mass Spectrometry CAMS) facility located at the Centro Nacional de Aceleradores (CNA, Seville, Spain). We determine the beam transport through the optical system using the transfer matrix formalism in two different approaches (ray tracing and the beam-envelope approach) and describe it in terms of cross section size and emittance. The beam size results given by MATLAB are compared with the measured beam size in three of the four image points that the system has, obtaining a good agreement between them. This suggests that the first-order transfer matrix formalism is enough to simulate the optical behavior of the system.The present version of this interface enables the user to control, interact with and display a beam transport system. Parameters involved in the optics such as voltages applied to the lenses, terminal voltage and charge state of the selected ion can be modified using this interface, which gives great generality, as the optics behavior of the AMS system can be simulated for any ion species prior to operation. (C) 2013 Elsevier B.V. All rights reserved.