ANSTO :: Browsing by Author "Stopic, A"

Browsing by Author "Stopic, A"

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Cultural heritage project at Australian Nuclear Science and Technology Organisation (ANSTO)
(Springer Nature, 2022-01-25) Salvemini, F; White, R; Levchenko, VA; Smith, AM; Pastuovic, Z; Stopic, A; Luzin, V; Tobin, MJ; Puskar, L; Howard, DL; Davis, J; Avdeev, M; Gatenby, S; Kim, MJ; Grazzi, F; Sheedy, K; Olsen, SR; Raymond, CA; Lord, C; Richards, C; Bevitt, JJ; Popelka-Filcoff, RS; Lenehan, CE; Ives, S; Dredge, P; Yip, A; Brookhouse, MT; Austin, AG
The Australian Nuclear Science and Technology Organization (ANSTO) is the home of Australia’s most significant landmark and national infrastructure for research. ANSTO operates one of the world’s most modern nuclear research reactors, OPAL; a comprehensive suite of neutron beam instruments; the Australian Synchrotron; the Electron Microscope Facility; and the Center for Accelerator Science. Over the years, the suite of nuclear methods available across ANSTO’s campuses has been increasingly applied to study a wide range of heritage materials. Since 2015 the strategic research project on cultural heritage was initiated in order to promote access to ANSTO’s capabilities and expertise, unique in the region, by cultural institution and researchers. This chapter offers a compendium of ANSTO nuclear capabilities most frequently applied to cultural heritage research. A series of innovative, interdisciplinary, and multi-technique studies conducted in close collaboration with Australian museums, institutions, and universities is also showcased. It includes research on dating Aboriginal Australian rock art and fingerprinting the sources of ochre pigments; rediscovering the technological knowledge in the making of early coinage and ancient weapons; virtually unwrapping the content of votive mummies from ancient Egypt; and investigating and restoring the original layer of a painting that can be explored by the museum audience in a novel type of exhibition based on an immersive, interactive, and virtual environment. © 2022 Springer Nature Switzerland AG
Groundwater tracing with nucleogenic 36Cl in West Canning Basin, Western Australia
(European Geosciences Union, 2017-04-26) Wilcken, KM; Cendón, DI; Meredith, KT; Simon, KJ; Stopic, A; Peterson, MA; Hankin, SI
Chlorine-36 has been used over the past 20-30 years as a groundwater tracer in many hydrological studies and is a well-established dating technique. Given the half-life of 301 kyr it is well suited for dating of ‘old’ groundwater between 50 kyr - 1 Myr. A challenge associated with utilising 36Cl as a tracer is that it can be produced via three different pathways that will influence the result based on the unique hydrogeological setting of a study area. Typically the dominant source of 36Cl in groundwater is atmospheric 36Cl that is produced at troposphere and stratosphere via interaction of cosmic-ray protons and secondary neutrons with Ar. However, the secondary cosmic-ray neutrons can similarly produce 36Cl in surface rocks particularly at high elevations. Also nucleogenic production of 36Cl at subsurface environments can become significant, especially if U and/or Th concentrations are high. Delineating and quantifying these processes is essential when using 36Cl as a groundwater dating tool. In contrast to a conservative situation where atmospheric 36Cl dominates, we present a study in the West Canning Basin located in the Pilbara region of Western Australia, where the 36Cl/Cl ratio increases from 30 10-15 near the recharge zone to 100 10-15 over a 60 km of flow path within a confined aquifer. Additional isotopic evidence (14C and 87Sr/86Sr) in groundwater, mineralogy (X-Ray diffraction) and elemental analysis (Neutron Activation) of whole-rock powder samples from the aquifer and overlying geological units, is used to establish an interpretation that nucleogenic 36Cl production is effectively the only potential process to explain the data. Nucleogenic production can influence the groundwater 36Cl content in two different ways: (1) as an additional input of Cl with a 36Cl/Cl ratio that reflects the neutron flux within the particular mineralogy; or (2) via “in-situ” production of 36Cl directly in the groundwater from the dissolved 35Cl where the rate is dictated by the neutron flux in the aquifer and the residence time. For this study, the whole-rock elemental composition is used to calculate the nucleogenic production within the aquifer and confining units of the groundwater system. This effectively ruled out both the Wallal sandstone aquifer and the overlying confining unit of the Jarlemai clay aquitard as the sources of 36Cl. Here we explore the idea that the underlying granite is the most likely source of 36Cl. © Author(s) 2017. CC Attribution 3.0 License.
Immobilization of iodine via copper iodide
(Elsevier, 2018-07) Vance, ER; Grant, C; Karatchevtseva, I; Aly, Z; Stopic, A; Harrison, JJ; Thorogood, GJ; Wong, HKY; Gregg, DJ
CuI is a candidate wasteform for the immobilization of the fission product 129I. CuI can be made simply by the addition of CuCl to an I− bearing solution such that exchange of Cl− with I− takes place. The CuI material can then be consolidated into a wasteform by sintering at approximately 550 °C in argon or by hot isostatically pressing at 550 °C with 100 MPa of pressure. A waste loading of greater than 60 wt.% is achievable with good water leach resistance, in keeping with the low solubility product of CuI. However, like the well known wasteform candidate AgI, CuI decomposes in water containing metallic Fe. To compensate this deficiency, the sintered CuI wasteform can be further protected by surrounding it by Sn powder and HIPing at the low temperature of 200 °C. © 2018 Elsevier B.V
An insight into a Shang dynasty bronze vessel by nuclear techniques
(MDPI, 2023-01-25) Salvemini, F; Patuovic, Z; Stopic, A; Kim, MJ; Gatenby, S
A bronze wine vessel attributed to 1600–1046 B.C., Shang dynasty in China, an object from the East Asian Collection of the Museum of Applied Arts and Sciences in Sydney (Australia), was studied using a non-destructive scientific analytical protocol based on the synergic combination of nuclear techniques. Gamma spectrometry, neutron-computed tomography, and proton-induced X-ray emission (PIXE) spectroscopy were applied to gain a better insight into the structural and compositional features of the artefact to prove its authenticity. Gamma spectrometry was performed to assess the risk of excessive sample activation induced by long exposure to the neutron beam and to determine the bulk elemental composition. Based on neutron-computed tomography, the porosities and the thickness of the metal wall were evaluated and found consistent with the piece-mould casting technology adopted by craftsmen during the Shang dynasty in China. Finally, PIXE spectroscopy demonstrated the use of a ternary (copper–tin-leaded) alloy and the nature of mineralisation on the surface. © 2023 The authors.
A Monte Carlo model of the Dingo thermal neutron imaging beamline
(Springer Nature, 2023-12-01) Jakubowski, K; Charcon, A; Tran, LT; Stopic, A; Garbe, U; Bevitt, JJ; Olsen, SR; Franklin, DR; Rosenfeld, AB; Guatelli, S; Safavi-Naeini, M
In this study, we present a validated Geant4 Monte Carlo simulation model of the Dingo thermal neutron imaging beamline at the Australian Centre for Neutron Scattering. The model, constructed using CAD drawings of the entire beam transport path and shielding structures, is designed to precisely predict the in-beam neutron field at the position at the sample irradiation stage. The model’s performance was assessed by comparing simulation results to various experimental measurements, including planar thermal neutron distribution obtained in-beam using gold foil activation and BC-coated microdosimeters and the out-of-beam neutron spectra measured with Bonner spheres. The simulation results demonstrated that the predicted neutron fluence at the field’s centre is within 8.1% and 2.1% of the gold foil and BC-coated microdosimeter measurements, respectively. The logarithms of the ratios of average simulated to experimental fluences in the thermal (E 0.414 eV), epithermal (0.414 eV < E 11.7 keV) and fast (E 11.7 keV) spectral regions were approximately − 0.03 to + 0.1, − 0.2 to + 0.15, and − 0.4 to + 0.2, respectively. Furthermore, the predicted thermal, epithermal and fast neutron components in-beam at the sample stage position constituted approximately 18%, 64% and 18% of the total neutron fluence. © The Authors - Open Access Open Access This article is licensed under a Creative Commons Attribution 4.0 International.
Rare earth elements and yttrium as tracers of waste/rock-groundwater interactions
(Elsevier, 2022-07-15) Cendón, DI; Rowling, B; Hughes, CE; Payne, TE; Hankin, SI; Harrison, JJ; Peterson, MA; Stopic, A; Wong, HKY; Gadd, PS
Fine particle air pollution is a significant problem in large urbanised areas across the Asian region. With funding from the International Atomic Energy Agency (IAEA) fifteen countries in Asia have been collecting weekly samples on filters of fine and coarse particles in major cities for the past 15 years. These filters have been analysed for over 20 different chemical species from hydrogen to lead using a range of analytical techniques including accelerator based ion beam techniques such as PIXE, PIGE, PESA, RBS, as well as XRF and NAA. These data have been included into a major database, which is generally available, containing over 17,000 combined sampling days from these fifteen countries spanning an area of the globe from ± 50° latitude and from 70° to 180° longitude. That is, the sampling covers an area north-south from Mongolia to New Zealand and west-east from Islamabad, Pakistan to Wellington, NZ. Crown Copyright © 2019 Published by Elsevier B.V.
Silver iodide sodalite for 129I immobilisation
(Elsevier B.V., 2016-11-01) Vance, ER; Gregg, DJ; Grant, C; Stopic, A; Maddrell, ER
Silver iodide sodalite was initially synthesised as a fine-grained major phase in a nominally stoichiometric composition following hot isostatic pressing at 850 °C with 100 MPa and its composition, Ag4Al3Si3O12I, was approximately verified by scanning electron microscopy. An alternative preparative method yielded a more dense and stoichiometric AgI sodalite on sintering and HIPing. As found for AgI, the I is released from AgI sodalite much more readily in reducing water than in ordinary water. Thus in normal PCT-B tests, the I release was <0.3 g/L in water, but it was ∼70 g/L under highly reducing conditions. This is an important point with regard to can material if HIPing is used for consolidation. © 2016 Elsevier B.V.
Silver iodide sodalite – wasteform / HIP canister interactions and aqueous durability
(Elsevier, 2019-04-15) Maddrell, ER; Vance, ER; Grant, C; Aly, Z; Stopic, A; Palmer, T; Harrison, JJ; Gregg, DJ
The use of silver zeolite for the capture of radioiodine from the vapour phase, followed by thermal conversion now appears to be the most direct route by which a sodalite wasteform can be formed. In addition, consolidation by hot-isostatic pressing (HIP) in sealed canisters has many significant advantages over conventional methods such as sintering or melting these candidate wasteforms. The choice of HIP canister material is important as reaction at the wasteform/HIP canister interface results in an interaction zone that can potentially produce detrimental phases, wasteform porosity and canister thinning. This paper builds on a previous study that demonstrated that iodine could be captured from the vapour phase using silver exchanged zeolite and converted to sodalite by HIPing in Fe HIP canisters. The Cu or Ni metal HIP canisters used in this work result in an ∼100–200 μm thick local interaction zone with a variety of chemistries. Durability studies were conducted using a variety of reducing conditions and clearly demonstrated the redox sensitivity of silver sodalite. While the silver sodalite wasteform produced is, like the popular AgI-based wasteforms, highly leach resistant to leaching by deionised water it was unstable under highly reducing conditions, which are likely to occur in most geological disposal facilities. Post leaching characterisation revealed the redeposition of AgI and the formation of an aluminosilicate alteration layer under some leaching conditions. Appropriate precautions are required should a silver sodalite wasteform for iodine immobilisation be exposed to reducing groundwater conditions. Crown Copyright © 2019 Published by Elsevier B.V.
Sm-146 – feasibility studies to re-date the chronology of the early solar system
(Australian Nuclear Science and Technology Organisation, 2021-11-17) Pavetich, S; Fifield, LK; Froehlich, MB; Koll, D; Slavkovská, Z; Stopic, A; Tims, SG; Wallner, A
AMS measurements of long-lived radionuclides can make significant contributions to the understanding of the temporal evolution of our early solar system. Samarium-146 has a half-life in the order of 100 Myr and decays via emission of α-particles into stable ¹⁴ ²Nd. Due to different geochemical behaviour and the radioactive decay of ¹⁴ ⁶ Sm, the Sm-Nd isotopic system can serve as a chronometer for the early solar system and planetary formation processes. The half-life of ¹⁴ ⁶ Sm, which provides the time scale for this clock, is in dispute. The most recent and notably precise measurements for the half-life are (103±5) Myr (adopted from [1,2]) and (68±7) Myr [3] and differ by more than 5 standard deviations. In addition to potentially resolving this discrepancy, developing AMS for ¹⁴ ⁶ Sm might provide the means to study stellar nucleosynthesis on the proton rich side of the chart of nuclei and serve as radiometric tracer for geosciences. Due to the extremely challenging task of separating ¹⁴ ⁶ Sm from its stable isobar ¹⁴ ⁶ Nd, to date the only AMS measurement of ¹⁴ ⁶ Sm was performed at Argonne National Laboratory with energies in the order of ~880 MeV. At the Heavy Ion Accelerator Facility at ANU, the possibility to measure ¹⁴ ⁶ Sm at energies of 200-250 MeV is being explored. Different sample materials, molecular negative ion beams and detector setups are investigated. So far, the lowest Nd backgrounds, from commercially available sample material without additional Nd separation were achieved using SmO₂ - beams extracted from Sm₂ O₃ samples. In order to explore the limits of the Sm detection capabilities, Sm₂ O₃ samples were irradiated with thermal neutrons in the reactor at ANSTO to produce the shorter lived ¹⁴ ⁵ Sm (t1/2 = (340±3) d [4]) via ¹⁴ ⁴ Sm(n,γ)¹⁴ ⁵ Sm. The production of ¹⁴ ⁵ Sm is easier and faster and the challenges in measuring ¹⁴ ⁵ Sm via AMS are very similar to those measuring ¹⁴ ⁶ Sm. In addition, ¹⁴ ⁵ Sm has the potential to serve as a tracer for future reference materials for AMS measurements of Sm.
Trace metal content in inhalable particulate matter (PM10 and PM2.5 collected from historical mine waste deposits using a laboratory-based approach
(Springer, 2016-05-05) Martin, R; Dowling, K; Pearce, DC; Florentine, S; McKnight, S; Stelcer, E; Cohen, DD; Stopic, A; Bennett, JW
Mine wastes and tailings are considered hazardous to human health because of their potential to generate large quantities of highly toxic emissions of particulate matter (PM). Human exposure to As and other trace metals in PM may occur via inhalation of airborne particulates or through ingestion of contaminated dust. This study describes a laboratory-based method for extracting PM2.5–10 (coarse) and PM2.5 (fine) particles from As-rich mine waste samples collected from an historical gold mining region in regional, Victoria, Australia. We also report on the trace metal and metalloid content of the coarse and fine fraction, with an emphasis on As as an element of potential concern. Laser diffraction analysis showed that the proportions of coarse and fine particles in the bulk samples ranged between 3.4–26.6 and 0.6–7.6 %, respectively. Arsenic concentrations were greater in the fine fraction (1680–26,100 mg kg−1) compared with the coarse fraction (1210–22,000 mg kg−1), and Co, Fe, Mn, Ni, Sb and Zn were found to be present in the fine fraction at levels around twice those occurring in the coarse. These results are of particular concern given that fine particles can accumulate in the human respiratory system. Our study demonstrates that mine wastes may be an important source of metal-enriched PM for mining communities.© 2016, Springer Science+Business Media Dordrecht.

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