Browsing by Author "Child, DP"
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- Item12th South Pacific Environmental Radioactivity Association Conference (SPERA 2012)(Australian Nuclear Science and Technology Organisation, 2012-10-16) Heijnis, H; Payne, TE; Lickiss, J; Bruhn, F; Zettinig, M; Zawadzki, AW; Hoffmann, EL; Child, DPWelcome to the 12th South Pacific Radioactivity Association Conference, welcome back in Sydney. The conference will be hosted by the Australian Institute for Nuclear Science and Engineering and the Australian Nuclear Science and Technology Organisation. The program for the 12th SPERA conference is very exciting, with key-note speakers setting the scene for a diverse range of sessions. The conference will conclude by offering the participants a tour of ANSTO’s new facilities. We would like to thank Jorden Lickiss for her tireless efforts in conference management. We also like to thank our sponsors AINSE, ANSTO and Nucletron for their financial support. We look forward to your participation and a successful conference.
- Item15th International Conference on Accelerator Mass Spectrometry(Australian Nuclear Science and Technology Organisation, 2021-11-15) Bertuch, F; Child, DP; Fink, D; Fülöp, RH; Hotchkis, MAC; Hua, Q; Jacobsen, GE; Jenkinson, A; Levchenko, VA; Simon, KJ; Smith, AM; Wilcken, KM; Williams, AA; Williams, ML; Yang, B; Fallon, SJ; Wallner, TOn behalf of the AMS-15 Organising committee, we would like to thank you for attending the 15th International Conference on Accelerator Mass Spectrometry. Held as an online event for the first time, the 2021 conference attracted over 300 attendees with presentations delivered by colleagues and professionals from around the globe.Applications of AMS to the world’s most pressing problems/questions: A-1 : Earth’s dynamic climate palaeoclimate studies, human impacts on climate, data for climate modelling. A-2 : Water resource sustainability groundwater dating, hydrology, water quality and management A-3 : Living landscapes soil production, carbon storage, erosion, sediment transport, geomorphology. A-4 : Catastrophic natural events volcanoes, cyclones, earthquakes, tsunamis, space weather, mass extinctions. A-5 : Advancing human health metabolic and bio-kinetic studies, bomb-pulse dating, diagnostics and bio-tracing. A-6 : Challenges of the nuclear age nuclear safeguards, nuclear forensics, nuclear waste management, nuclear site monitoring, impacts of nuclear accidents. A-7 :Understanding the human story archaeology, human evolution and migration, history, art and cultural heritage A-8 : Understanding the cosmos fundamental physics, nuclear astrophysics, nuclear physics AMS Research and Development: T-1 : Novel AMS systems, components and techniques T-2 : Suppression of isobars and other interferences T-3 : Ion sourcery T-4 : New AMS isotopes T-5 : Advances in sample preparation T-6 : Data quality and management T-7 : Facility Reports (Poster Presentation only)
- Item7Be and 10Be concentrations in recent firn and ice at Law Dome, Antarctica(Elsevier, 2000-10-01) Smith, AM; Fink, D; Child, DP; Levchenko, VA; Morgan, VI; Curran, MAJ; Etheridge, DM; Elliott, GOver the past three years, the Australian National Tandem for Applied Research (ANTARES) AMS facility at ANSTO has been expanding its sample preparation and measurement capability, particularly for 10Be, 26Al and 36Cl. During this time, ANSTO has continued its collaboration with the AAD and CSIRO Atmospheric Research on the measurement of cosmogenic isotopes from Law Dome, Antarctica. This research program has been supported by the construction of a dedicated geochemistry laboratory for the processing of ice and rock samples for the preparation of AMS targets. Here we present our first results for 10Be concentrations measured in ice cores from three sites at Law Dome and describe the sample processing protocol and aspects of the AMS measurement procedure. These sites are characterised by an eightfold difference in accumulation rate with a common precipitation source. In combination with an established ice chronology, this has enabled some preliminary findings concerning the relationship between the snow accumulation rate and the measured 10Be concentration for Law Dome during recent times. Additionally, we present 7Be and 10Be/7Be measurements made for a few surface snow samples from Law Dome and Australia. © 2000 Elsevier Science B.V.
- ItemAccelerator mass spectrometry measurements of 233U in groundwater, soil and vegetation at a legacy radioactive waste site(Elsevier, 2024-06) Payne, TE; Harrison, JJ; Child, DP; Hankin, SI; Hotchkis, MAC; Hughes, CE; Johansen, MP; Thiruvoth, S; Wilsher, KLLow-level radioactive wastes were disposed at the Little Forest Legacy Site (LFLS) near Sydney, Australia between 1960 and 1968. According to the disposal records, 233U contributes a significant portion of the inventory of actinide activity buried in the LFLS trenches. Although the presence of 233U in environmental samples from LFLS has been previously inferred from alpha-spectrometry measurements, it has been difficult to quantify because the 33U and 234U α-peaks are superimposed. Therefore, the amounts of 233U in groundwaters, soils and vegetation from the vicinity of the LFLS were measured using accelerator mass spectrometry (AMS). The AMS results show the presence of 233U in numerous environmental samples, particularly those obtained within, and in the immediate vicinity of, the trenched area. There is evidence for dispersion of 233U in groundwater (possibly mobilised by co-disposed organic liquids), and the data also suggest other sources of 233U contamination in addition to the trench wastes. These may include leakages and spills from waste drums as well as waste burnings, which also occurred at the site. The AMS results confirm the historic information regarding disposal of 233U in the LFLS trenches. The AMS technique has been valuable to ascertain the distribution and environmental behaviour of 233U at the LFLS and the results demonstrate the applicability of AMS for evaluating contamination of 233U at other radioactive waste sites. © 2024 Australian Nuclear Science and Technology Organisation. Published by Elsevier Ltd. This is an open access article under the CC BY license
- ItemAccumulation of plutonium in mammalian wildlife tissues following dispersal by accidental-release tests(Elsevier, 2016-01-01) Johansen, MP; Child, DP; Caffrey, EA; Harrison, JJ; Hotchkis, MAC; Payne, TE; Ikeda-Ohno, A; Thiruvoth, S; Beresford, NA; Twining, JR; Davis, EWe examined the distribution of plutonium (Pu) in the tissues of mammalian wildlife inhabiting the relatively undisturbed, semi-arid former Taranaki weapons test site, Maralinga, Australia. The accumulation of absorbed Pu was highest in the skeleton (83% ± 6%), followed by muscle (10% ± 9%), liver (6% ± 6%), kidneys (0.6% ± 0.4%), and blood (0.2%). Pu activity concentrations in lung tissues were elevated relative to the body average. Foetal transfer was higher in the wildlife data than in previous laboratory studies. The amount of Pu in the gastrointestinal tract was highly elevated relative to that absorbed within the body, potentially increasing transfer of Pu to wildlife and human consumers that may ingest gastrointestinal tract organs. The Pu distribution in the Maralinga mammalian wildlife generally aligns with previous studies related to environmental exposure (e.g. Pu in humans from worldwide fallout), but contrasts with the partitioning models that have traditionally been used for human worker-protection purposes (approximately equal deposition in bone and liver) which appear to under-predict the skeletal accumulation in environmental exposure conditions. © 2015, Elsevier Ltd.
- ItemAccumulation of plutonium in mammalian wildlife tissues: comparison of recent data with the ICRP distribution models(International Conference on Radioecology and Environmental Radioactivity, 2014-07-01) Johansen, MP; Child, DP; Davis, E; Hotchkis, MAC; Payne, TE; Ikeda-Ohno, A; Twining, JRWe examined the distribution of plutonium (Pu) in the tissues of mammalian wildlife to address the paucity of such data under environmental exposure conditions. Pu activity concentrations were measured in Macropus rufus (red kangaroo), Oryctolagus cuniculus (European rabbit), and Pseudomys hermannsburgensis (sandy inland mouse)inhabiting the relatively undisturbed, semi-arid conditions at the former Taranaki weapons test site at Maralinga, Australia. Of the absorbed Pu (distributed via circulatory and lymph systems) accumulation was foremost in bone (83% ±10% SD), followed by muscle (9% ±10%), liver (7% ±7%), kidneys (0.5% ±0.3%), and heart (0.4% ±0.4%). The bone values are higher than those reported in ICRP 19 and 48 (45-50% bone), while the liver values are lower than ICRP values (30-45% liver). The ICRP values were based on data dominated by relatively soluble forms of Pu, including prepared solutions and single-atom ions produced by decay following the volatilisation of uranium during nuclear detonation (fallout Pu, ICRP 1986). In contrast, the Maralinga data relates to low-soluble forms of Pu used in tests designed to simulate accidental release and dispersal. We measured Pu in lung, GI-tract and the skin and fur as distinct from the absorbed Pu in bone, liver, muscle, and kidneys. Compared with the mean absorbed activity concentrations, the results for lung tissues were higher by up to one order of magnitude, and those in the GI tract contents and the washed skin/fur were higher by more than two orders of magnitude. These elevated levels are consistent with the presence of low-soluble Pu, including particulate forms, which pass through, or adhere upon, certain organs, but are not readily absorbed into the bloodstream. This more transitory Pu can provide dose to the lung and GI tract organs, as well as provide potential transfer of contamination when consumed in predator-prey food chains, or during human foodstuff consumption. For example, activity concentrations in O. cuniculus edible samples prepared according to traditional aboriginal methods were more than two orders of magnitude higher than in muscle alone. The increase was due to inclusion of GI tract components and contents in the traditional method. Our results provide new insights into the sequestration of Pu in mammalian tissues under environmental exposure conditions. These results contrast with those related to the specific forms of Pu and exposure conditions upon which the ICRP models were based. However, they provide data relevant to the assessment of key environmental legacy waste sites, and of potential release scenarios for the low-soluble oxide forms in the growing worldwide inventory of Pu associated with power production.
- ItemAchieving the ultimate sensitivity in Accelerator Mass Spectrometry of high mass isotopes(Australian National University, 2019-09-09) Hotchkis, MAC; Child, DP; Williams, ML; Wallner, A; Froehlich, MB; Koll, DThe VEGA AMS system at ANSTO, based on a 1MV tandem accelerator, was custom-designed to achieve the highest possible sensitivity for high mass isotopes. It incorporates multiple medium-resolving power analysing elements: one magnetic element for the injected negative ions, followed by magnetic, electrostatic and second magnetic elements for positive ions after acceleration. This design, with mass and energy resolving powers in the range 500 to 1000, separates isotopes and suppresses backgrounds that may originate from a variety of ion species. The gas stripper in the high-voltage terminal is key both to system efficiency and to background suppression. Helium gas stripping is used, providing around 40% ion yield to the most abundant charge state (3+). The stripper pressure must be sufficient to break up all molecules while minimising the scattering angle of the ions as they undergo charge-changing collisions. Our recent work has demonstrated that the need for production of negative molecular ions in AMS of actinides is not such a barrier to high efficiency: the VEGA sputter ion source can achieve greater than 1% efficiency for production of plutonium oxide negative ions and so overall sensitivity to a few hundred atoms in a sample is possible. We are involved in a number of projects requiring high sensitivity and low backgrounds. Examples include the detection of 244Pu of extraterrestrial origin in deep oceanic ferromanganese crusts; radioecology of plutonium in the environment of former nuclear test sites; detection of nuclear signatures for nuclear safeguards and forensics; use of Pu in global fallout as a chrono-marker in environmental studies; measurement of platinum-group-element isotope ratios in meteorites; evaluation of the radio-purity of materials for use in dark matter searches. Each of these projects presents their own particular challenges. In some cases, sensitivity is limited by background from scattered ions of species other than the one of interest. In other situations, cross-contamination between samples, in the sample prep lab or ion source, limits sensitivity. Other projects or previous uses of laboratories may leave residual contamination. For stable and very long-lived species, such as PGEs and major uranium isotopes, the ubiquity of those species at low levels in almost all materials sets limits. © The Authors.
- ItemActinides AMS for nuclear safeguards and related applications(Elsevier, 2010-04) Hotchkis, MAC; Child, DP; Zorko, BThe nuclear safeguards system which is used to monitor compliance with the Nuclear Non-proliferation Treaty relies to a significant degree on the analysis of environmental samples. Undeclared nuclear activities can be detected through determination of the isotopic ratios of uranium and plutonium in such samples. It is necessary to be able to measure plutonium at the femtogram level in this application, and measure the full suite of uranium isotopes (233–238U) where the total uranium content may be at the nanogram level. In this paper we describe the development of our accelerator mass spectrometry system for such analyses, with particular reference to recent improvements in our methods. The commissioning of a fast isotope cycling system for actinides has led to improved precision, with reproducibility of 4% for actinide isotope ratios. The background level for the key rare isotope 236U is found to be 8.8 fg, for total uranium content in the nanogram range, and is limited by 236U contamination rather than ion mis-identification. For plutonium the background is at the low femtogram level. © 2009 Published by Elsevier B.V.
- ItemActinides AMS for nuclear safeguards and related applications(Elsevier, 2010-04) Hotchkis, MAC; Child, DP; Zorko, BThe nuclear safeguards system which is used to monitor compliance with the Nuclear Non-proliferation Treaty relies to a significant degree on the analysis of environmental samples. Undeclared nuclear activities can be detected through determination of the isotopic ratios of uranium and plutonium in such samples. It is necessary to be able to measure plutonium at the femtogram level in this application, and measure the full suite of uranium isotopes (233-238U) where the total uranium content may be at the nanogram level. In this paper we describe the development of our accelerator mass spectrometry system for such analyses, with particular reference to recent improvements in our methods. The commissioning of a fast isotope cycling system for actinides has led to improved precision, with reproducibility of 4% for actinide isotope ratios. The background level for the key rare isotope 236U is found to be 8.8 fg, for total uranium content in the nanogram range, and is limited by 236U contamination rather than ion mis-identification. For plutonium the background is at the low femtogram level. © 2009 Published by Elsevier B.V. All rights reserved.
- ItemActinides AMS on the VEGA accelerator(Elsevier B. V., 2019-01-01) Hotchkis, MAC; Child, DP; Froehlich, MB; Wallner, A; Wilcken, KM; Williams, MLThe VEGA 1MV accelerator at ANSTO is designed to be a highly versatile AMS instrument. In this paper we focus on describing those aspects of the system that are designed to optimise its performance for actinides isotopic analysis, in particular the implementation of fast isotope cycling and multiple isotope detection methods to enable isotope detection across a wide range of rates and currents. Charge state yields are reported in the energy range from 0.3 to 1.0 MeV with helium gas stripping, showing that the highest yield for the 3+ charge state occurs around 1 MeV and exceeds 40%. Accuracy and precision for uranium isotope ratios are shown to approach 1% over a wide range of concentrations and isotope ratios. The ionisation efficiency for plutonium is shown to exceed 3%, leading to overall detection efficiency over 1%. In the absence of background, this leads to sub-attogram detection limits for several Pu isotopes including 244Pu. Crown Copyright © 2018 Published by Elsevier B.V.
- ItemActinides AMS sample processing capability at ANSTO – a tour by poster(Australian Nuclear Science and Technology Organisation, 2021-11-17) Child, DP; Hotchkis, MACDesigning and developing sample processing facilities for processing of samples for actinides analysis poses some unique challenges. Facilities for actinide research need to be tailored to specific application areas, sample composition for each area of research may contain isotopic ratio mixtures and isotopic concentrations incompatible with the sensitivity requirements and background/blank levels of adjacent projects. This is due to the widely varying sample compositions related to the source of the actinides, for example age dating of nuclear materials compared to safeguards analysis of uncontaminated swipe samples. The Actinides AMS capability at ANSTO’s Centre for Accelerator Science is operated by a small research group focussed on providing support for government, academic and industry users, and stakeholder projects. These facilities have been designed with versatility in mind, specialising on provision of high sensitivity analyses for low activity samples and projects to support the greatest breadth of applications. The current range of research applications supported include: Environmental occurrence and distribution of anthropogenic actinides - Actinides bomb pulse dating and tracing – geomorphology - Radioecology - biological uptake of nuclear activities environmental release Non-proliferation and monitoring - Nuclear Safeguards – swipe sample monitoring and wide area environmental sampling - Nuclear Forensics - nuclear material characterisation and dating - Environmental monitoring – emergency response, contamination monitoring, baseline studies Actinides from astrophysical events The Actinides AMS chemistry laboratory has been purpose built for low level environmental actinides sample preparation, in particular for high sensitivity low abundance actinides isotope (²³³U, ²³⁶ U, ²³⁹ Pu, ²⁴ ⁰ Pu, ²⁴ ¹Pu, ²⁴ ⁴ Pu), allowing for segregation of “dirty” operations (unpacking and handling of dried environmental materials) to progressively cleaner environments whilst still allowing for aggressive sample destruction and dissolution. To achieve this a range of specialised sample preparation components and configurations have been employed to allow for a wide range of sample types (swipes/filters, soils/sediments, biota, water, minerals) with elimination of possibility of sample crosstalk, dust and external atmospheric ingress and contamination. This is especially important given the potential for high dynamic ranges of isotopic concentrations between consecutively handled research projects. To support research applications unable to be handled in the AMS Actinides laboratory, partnered facilities with capability to process active materials are utilised to pre-treat samples and deliver subsamples suitable for handling in the low-level AMS laboratories. We present here the methodologies, processes and backgrounds achieved to deliver high sensitivity actinide samples for a range of applications and give the current status of the Actinides AMS capability.
- ItemActinides isotopic analysis using a 1 MV AMS system(University of Jyväskylä, Finland, 2016-07-03) Hotchkis, MAC; Child, DP; Wilcken, KM; Kitchen, RThe VEGA 1 MV AMS system at ANSTO has been custom-designed to cover analysis of a wide range of long-lived radioisotopes, including routine radiocarbon analysis and multiple-isotope analysis of actinides. The system incorporates 1.0 m radius injection and analysing magnets with o -axis cups on high and low mass sides. Following the analysing magnet, rare isotope beams pass through a 1m radius spherical electrostatic analyser and a 120 1 m radius magnet. The detector station consists of a two-anode gas detector, with o -axis options to direct isotopes to either a Faraday cup or an electron multiplier ion counter. All three analysing magnets are fitted with electrostatic bouncer systems. At the LE end, the bouncer works in the usual way for all isotope combinations of interest, including 12C-13C-14C and actinides. The HE bouncers are used to transmit a range of masses of interest for actinides analysis, for example mass 239 to 244 Pu isotopes. For uranium analysis, the less rare isotopes can be directed to o axis cups or the ion counter. Software has been implemented to enable a high degree of exibility in analysing up to 8 isotopes at a time. In this paper we present details of the system and its performance and applications. © The Authors
- ItemAMS measurement of 129I, 36C1 and 14C in underground waters from Mururoa and Fangataufa atolls(Elsevier, 2000-10) Jacobsen, GE; Hotchkis, MAC; Fink, D; Child, DP; Tuniz, C; Sacchi, E; Levins, DM; Povinec, PP; Mulsow, SAMS analyses of 36Cl, 129I and 14C in underground water have been performed as part of IAEA’s assessment of the radiological situation at Mururoa and Fangataufa atolls. The samples consisted of waters from monitoring wells, and from two cavity-chimneys created by underground nuclear tests. The water samples from the monitoring wells contained varying concentrations of radionuclides, with the highest concentrations of radionuclides found in the two test cavity-chimneys. A comparison of the concentrations of radionuclides determined by AMS, 36Cl and 129I, and with radionuclides determined using conventional methods, 3H, 90Sr and 137Cs, shows a reasonable correlation. However, some differences in behaviour, mainly attributed to differences in the sorption characteristics of the elements, are discernible. The concentrations of radionuclides in the underground environment were used to validate geosphere transport models. © 2000 Elsevier Science B.V.
- ItemAnalysis of hot particle characteristics affecting environmental fate and interaction with living organisms(SPERA, 2016-09-09) Johansen, MP; Child, DP; Collins, RN; Hotchkis, MAC; Howell, NR; Payne, TE; Ikeda-Ohno, A; Mokhber-Shahin, LThe 2nd International Conference on the Sources, Effects and Risks of Ionizing Radiation (SERIR-2) and the 14th Biennial Conference of the South Pacific Environmental Radioactivity Association (SPERA-2016) and will be held in Bali, Indonesia 5-9 September 2016. The South Pacific Environmental Radioactivity Association (SPERA), in conjunction with the Indonesian National Nuclear Energy Agency (BATAN) and the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) made the decision to jointly hold these conferences in one week at the same venue to avoid topical overlap and to strengthen regional participation at both events. SERIR2 will be a 1-day conference (5 September) and deals with the efforts to enhance data collection and disseminate scientific findings related to the issues of sources, effects and risks of the ionizing radiation, as well as to seek ways of communicating with stakeholders (scientific communities, regulatory authorities and general public) on those issues. The 14th Biennial Conference of the South Pacific Environmental Radioactivity Association (SPERA), to be held 6-9 September, provides a platform for discussion and debate among scientists on the occurrence, behaviour, impact and measurement of radioactive species present in the environment through natural processes, or resulting from human activities. This international conference facilitates knowledge sharing on environmental radioactivity and related topics of local and global significance. The joint conference will be held 5-9 September 2016, with a welcome reception on 4 September, at the Sanur Paradise Plaza Hotel in Bali. The joint conference will include a one-day workshop on the 6 September on topic(s) to be decided.
- ItemThe ANTARES AMS facility at ANSTO(Elsevier, 2004-08) Fink, D; Hotchkis, MAC; Hua, Q; Jacobsen, GE; Smith, AM; Zoppi, U; Child, DP; Mifsud, C; van der Gaast, H; Williams, A; Williams, MThis paper presents an overview of ANTARES operations, describing (1) technical upgrades that now allow routine 0.3–0.4% 14C precision for 1 mg carbon samples and 1% precision for 100 micrograms, (2) proficiency at 236U measurements in environmental samples, (3) new developments in AMS of platinum group elements and (4), some major application projects undertaken over the period of the past three years. Importantly, the facility is poised to enter into a new phase of expansion with the recent delivery of a 2 MV 14C tandem accelerator system from High Voltage Engineering (HVE) and a stable isotope ratio mass spectrometer from Micromass Inc. for combustion of organic samples and isotopic analysis. © 2004 Elsevier B.V.
- ItemA bright future for accelerator science at ANSTO(Australian Institute of Nuclear Science and Engineering (AINSE), 2009-11-25) Hotchkis, MAC; Child, DP; Cohen, DD; Dodson, JR; Fink, D; Garton, DB; Hua, Q; Ionescu, M; Jacobsen, GE; Levchenko, VA; Mifsud, C; Siegele, R; Smith, AM; Williams, AG; Winkler, SIn the May 2009 budget, the Federal Government announced funding of $25m to ANSTO through the Education Investment Fund, to build state-of-the-art applied accelerator science facilities, by upgrading and replacing existing facilities and laboratories at ANSTO. Currently, ANSTO's researchers, jointly with researchers from all 37 Australian universities, plus other agencies such as CSIRO, government departments and local government bodies, and overseas collaborators and customers, use ANSTO's accelerator facilities for analysis of a wide range of materials, predominantly by Accelerator Mass Spectrometry (AMS) and Ion Beam Analysis (IBA). There are >100 external users of those facilities every year. © 2009 AINSE
- ItemThe Centre for Accelerator Science at ANSTO(International Atomic Energy Agency, 2014-01-14) Hotchkis, MAC; Child, DP; Cohen, DD; Dodson, JR; Fink, D; Fujioka, T; Garton, DB; Hua, Q; Ionescu, M; Jacobsen, GE; Levchenko, VA; Mifsud, C; Pastuovic, Z; Siegele, R; Smith, AM; Wilcken, KM; Williams, AGIn 2009, the Federal government provided funding of $25m to ANSTO through the Education Investment Fund, to build state-of-the-art applied accelerator science facilities, with the primary aim of providing world-leading accelerator mass spectrometry (AMS) and ion beam analysis (IBA) facilities. New buildings are now under construction and Building plans are now well advanced, and two new accelerators are on order with National Electrostatics Corporation, USA. The 1MV AMS accelerator system is designed with the capability to perform high efficiency, high precision AMS analysis across the full mass range. Large beam-optical acceptance will ensure high quality and high throughput radiocarbon measurements. High mass resolution analyzers, at low and high energy, coupled to a novel fast isotope switching system, will enable high quality analysis of actinide radioisotopes. The 6MV tandem accelerator will be instrumented with a wide range of AMS, IBA and ion irradiation facilities. The three ion sources include hydrogen and helium sources, and a MCSNICS sputter source for solid materials. The AMS facility has end stations for (i) a gasabsorber detector for 10Be analysis, (ii) a time-of-flight detector, (iii) a gas-filled magnet and(iv) a general use ionization detector suited to 36Cl and other analyses. Initially, there will be four IBA beamlines, including a new ion beam microprobe currently on order with Oxford Microbeams. The other beamlines will include an on-line ion implanter, nuclear reaction analysis and elastic recoil detection analysis facilities. The beam hall layout allows for future expansion, including the possibility of porting the beam to the existing ANTARES beam hall for simultaneous irradiation experiments.Two buildings are currently under construction, one for the new accelerators and the other for new chemistry laboratories for AMS and mass spectrometry facilities. The AMS chemistry labs are planned in two stages, with the new radiocarbon labs to come in the second phase of work.
- ItemChallenges in the radiochemical separation of marine samples from the Montebello Islands(South Pacific Environmental Radioactivity Association, 2018-11-06) Thiruvoth, S; Child, DP; Harrison, JJ; Johansen, MP; Silitonga, A; Vardanega, CR; Wilsher, KL; Wong, HKYThe Montebello Islands, located off the North Western coast of Western Australia, was used as a nuclear weapons test site by the British government in the 1950s. Three nuclear tests were conducted around the islands. The first in 1952 (W818) detonated in the hull of the HMS Plym anchored in 12 m of water between Alpha and Trimouille Islands, and the second and third tests (MOSAIC G1 and G2) were detonated on 30 m Aluminium towers in May and June 1956, G1 on the Northern Western tip of Trimouille island and G2, the largest test conducted in Australian territory, on Alpha island. The fallout from these tests deposited long-lived anthropogenic radionuclides on nearby islands and ocean surface, host to an array of animals and plants. Marine sand, marine sediment, algae, fish, turtles and turtle eggs, among others, were sampled from the surrounding zones for dose assessment studies, thirty-nine of which were processed for actinide and strontium analysis. Due to the expected presence of discrete radioactive particles in some matrices a three step digestion method was applied to obtain complete dissolution of sample material. To overcome sample heterogeneity, the digest solution was sub-sampled for actinide and Sr-90 analysis by alpha spectrometry and liquid scintillation analysis, for plutonium isotopic analysis by AMS, and for elemental analysis by ICPAES/MS. The radiochemical separation method developed at ANSTO for Am, Pu, Th, U, and Sr for terrestrial soils and sediments (Harrison et al, 2011) was adapted to samples from the marine environment. However, some sample matrices proved to be challenging in achieving acceptable chemical recoveries of strontium due to the high concentrations of native calcium. This current study will discuss the methods used, and challenges overcome, in radiochemical separation for alpha spectrometry and liquid scintillation analysis for a wide range of sample types.
- ItemCharacterisation of anthropogenic radioactive particles from former weapon test sites in Australia(South Pacific Environmental Radioactivity Association, 2018-11-06) Young, EL; Johansen, MP; Child, DP; Hotchkis, MAC; Howell, NR; Pastuovic, Z; Howard, DL; Palmer, T; Davis, JFormer nuclear test sites on Australian territories such as those at Maralinga and the Montebello islands have been remediated to varying extents but wide-spread radioactivity still remains. Fission and neutron-activation products at the test sites have been decaying over time but long-lived radioisotopes such as uranium and plutonium persist within the environment, predominantly in the form of discrete particles. These particles vary widely in composition depending upon the detonation characteristics and local geology, and are widely dispersed around each site. Radioactive particles are the dominant form of radionuclides at the former test sites and the future distribution of radioactive contaminants in the environment at these sites is largely dependent upon their fate and behaviour. The weathering of particles in the environment and the potential release of the radioactivity they contain is influenced by a range of factors including particle morphology, elemental composition and chemical form, and the prevailing environmental conditions. Radioactive particles have been isolated from soils and sediments from Australian test sites and characterised using photostimulated luminescence (PSL)-autoradiography, scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDS), Synchrotron X-ray fluorescence microscopy (XFM) and particle-induced X-ray emission (PIXE). The characteristics of the particles and potential implications for their long term fate will be discussed in the context of the techniques applied and the environments in which the particles were found.
- ItemChoosing the right stripper gas from AMS and other applications with tandem accelerators at low and medium terminal voltage(Department of Nuclear Physics Research School of Physics and Engineering, The Australian National University, 2013-04-11) Hotchkis, MAC; Child, DP; Fink, D; Levchenko, VA; Wilcken, KMRecent experimentation with stripper gases used for Accelerator Mass Spectrometry (AMS) has seen a divergence in the practices adopted at laboratories performing AMS of high mass species (such as actinides) at low and medium terminal voltages. At low voltages (<1 MV), the Ion Beam Group at ETH Zurich has demonstrated the advantages of using helium as the stripper gas, for both radiocarbon AMS [1] and for actinides AMS [2]. Meanwhile, at ANSTO we have investigated several gases at 4 MV [3, 4] and find that a multi–atom molecular gas such as sulphur hexafluoride provides the best yield for actinides AMS. In both cases, data published 40 years ago provided clues as to the optimum gas in each situation.