Description
Poster Session A
The most common ion source of AMS instruments, the cesium sputter source (Middleton 1983), demands a substantial share of the regular maintenance work and causes a considerable number of operation interruptions. One reason is the difficulty of obtaining meaningful diagnostic measurements under the rough conditions inside. In addition to the high temperature and the strong electric fields, the...
Graphite target preparation is one of the key steps in accelerator mass spectrometry (AMS) radiocarbon chronology measurement, so it is crucial to make the graphitisation process simple and efficient. In traditional methods, desulphurisation of samples containing sulphur is essential, as sulphur can affect the yield of graphitisation, and usually requires the addition of silver to form Ag2S to...
Plutonium (Pu) is recognized as an essential environmental indicator isotope. The purpose of this investigation is to devise a protocol for extracting plutonium from soil samples, aimed at Accelerator Mass Spectrometry (AMS) analysis. The procedure initiates with the purification and ashing of samples, followed by the integration of the standard reference material 242Pu before proceeding to...
The most powerful anthropogenically influenced greenhouse gas after carbon dioxide is methane. Its atmospheric mixing ratio is much lower than of CO2, but the global warming potential of CH4 is more than eighty times higher, on a 20-year timescale (IPCC, 2021). The atmospheric amount of CH4 has been growing rapidly since 2007, and the reasons are unclear. Several types of sources can...
In this paper we apply cosmogenic nuclide dating to the selected key archaeological sites in the western Mediterranean region (southern Spain and Morocco), to provide better chronological constrains to sites where previous geochronological data were scarce, scattered or unresolved. Our knowledge on the early hominin dispersal out of Africa, e.g., timing, causes, pathways, remain incomplete....
Mass of Li molecule (Li2) is same to 14C, so 14C measurement is frequently interfered by it in using two plus ion of 14C after gas striping of AMS. Removal of Li molecule (Li2) is important in our AMS which use two plus ion of 14C. AMS generate negative ions of carbon (12C-, 13C-, 14C-) and Li2- in a source, which have binding energies of electron of 1.262eV, 982.35nm(14C-) and 0.42eV, 2.952nm...
Strontium-90 (T$_{1/2}$ = 28.90 a) is among the most prominent fission products produced with high yield in the nuclear fuel cycle and nuclear weapons tests. It is very mobile in the environment and due to its chemical similarities to calcium it easily accumulates in bones and teeth following ingestion or inhalation. However, $^{90}$Sr is not only of environmental interest for its...
The solar neighborhood lies within the Local Bubble, a low-density region of space formed by stellar explosions [1]. The Local Interstellar Cloud (LIC) with the solar system inside is embedded in this cavity. Assuming the LIC contains remnants from supernovae events, the solar system may accumulate traces of long-lived supernova-produced radionuclides as it traverses the LIC. The radionuclide...
AMS, as an ultra-sensitive method, is increasingly used in the determination of 14C for studies on wide variety of fields. As a multi-nuclide 14C extended AMS system, TJUAMS has been operating at Tianjin University for seven years. The sample throughput of measured 14C has exceeded 6000. During the long-term 14C-AMS measurements and data processing, some new discoveries and ideas, such as the...
The rare radioisotope Sr-90 is one of the most important products of thermal neutron fission. On one hand, the Sr-90 yield from fission is relatively large;on the other hand, 90Sr is known for its bone-seeking radiotoxicity and the risk of causing bone cancer. Currently, researches related to 90Sr are facing the challenge of measuring the concentration of Sr-90 environmental samples, which...
Surface exposure dating, which calculates the exposure age of rocks based on the accumulation of in-situ cosmogenic nuclides on the ground surface, is a very useful technique for directly dating the age of exposed rocks. Surface exposure dating has many advantages, but the required high-precision measurement is not easy. This is mainly due to the extremely low abundance of cosmogenic nuclides....
Human activity-induced soil erosion and rock desertification in southern China's karst areas is a severe problem for the local economy and stability of ecosystem. However, it is challenge to quantitatively link the human activity-induced soil erosion to the local rock desertification by traditional geochemistry methods. In this study, we explored pyrolysis-combustion technology to partition...
In order to better characterize carbonaceous components in atmospheric aerosols and to assess the contributions of biomass sources in the carbonaceous aerosols in the regions where heavily influenced by field burning of agricultural wastes, we collected carbonaceous aerosols at the summit of Mt. Tai (1534 m above sea level) on a daytime and nighttime basis during a summertime campaign...
Cooling water is an essential part of the infrastructure of all but the smallest AMS instruments, and of particle accelerators in general. While facilities situated on larger scientific campuses often can rely on good quality water from a central supply, many instruments, including VERA at the University of Vienna, are situated on sites where a stand-alone provision is necessary. Because it is...
The positive ion source mass spectrometry is currently undergoing extensive research and development, being regarded as a more compact and cost-effective alternative to conventional tandem accelerator mass spectrometers. However, its elimination of the accelerator design presents challenges in overcoming the instability of low-energy carbon ion beams extracted by the Electron Cyclotron...
In 2018, an Ionplus 200 kV MIni-CArbon DAting System (MICADAS) Accelerator Mass Spectrometer (AMS) was installed at the Laboratory of AMS Dating and the Environment, Nanjing University (NJU-AMS Laboratory), China. The NJU-AMS Laboratory is largely devoted to research on radiocarbon dating and 14C analysis in fields of earth, environmental and archaeological sciences. The laboratory has...
In the context of today's global warming, China has proposed the carbon emission reduction target of carbon peaking and carbon neutrality, while the increase in atmospheric carbon dioxide concentration is mainly caused by man-made fossil fuel emissions. Radiocarbon isotope (14C) is the most effective tracers of fossil fuel CO2 (CO2ff). In this study, 5-liter air bags and PQ200 instrument were...
210Po, AMS 14C, 230Th/U dating and stable C/O isotope records of two stalagmites from South Ural, Russia
Hao-Ting Chiu1, Hong-Chun Li1,*, Tzu-Tsen Shen1, Dilyara Kuzina2, Satabdi Misra1, Horng-Sheng Mii 3, Lisheng Wang4, Zhibang Ma4
- Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan, ROC (hcli1960@ntu.edu.tw)
- Institute of Geology and Petroleum...
Radiocarbon detection and analysis is of great importance due its applications in dating and tracer for earth science, archaeology, forensic science, environmental evaluation, material analysis, metabolism, pharmacology and so on. Besides the well-known accelerator mass spectrometry (AMS) and liquid scintillation counting (LSC), optical technologies such as linear absorption spectroscopy,...
Cl is a ubiquitous element in the environment. 36Cl ,half-life is 3.01x105a. The dating range can be up to 3.01x106a (10 times half-life), which covers the whole Quaternary period, has a unique advantage for the determination of Quaternary stratigraphy and Quaternary age. In recent years, with the continuous development of gas pedal mass spectrometry (AMS) technology, 36Cl has been measured...
A two-year (March 2021 to February 2023) continuous atmospheric CO2 and a one-year regular atmospheric 14CO2 measurement records were measured at the northern foot of the Qinling Mountains in Xi’an, China, aiming to study the temporal characteristics of atmospheric CO2 and the contributions from the sources of fossil fuel CO2 (CO2ff) and biological CO2 (CO2bio) fluxes. The two-year mean CO2...
Using helium as the stripping medium has become a dominant trend in 14C-AMS miniaturization. In order to explore how to utilize lower-energy beam for 14C analysis, more experimental data on low-energy C-He collisions are needed. In this work, the charge state yield versus target thickness after C- and helium collisions at 70-220 keV was investigated using the GXNU-AMS system, and the charge...
This report presents the radiocarbon dating results obtained for these Egyptian materials from the Kyoto University Museum, including Coptic textiles, mummy cloth and sandals. It also reports on the material database, the Kyoto University Research Information Repository, which includes radiocarbon dates and material analyses.
The Coptic Textile Collection of Egyptian Archaeological Materials...
The understanding of the formation of the elements has been an intriguing topic within the last decades. It is now proven that the heaviest naturally occurring elements, the actinides, are produced in the astrophysical r-process. However, the exact site of this process is still under debate. Recently, the amount of interstellar $^{244}$Pu (T$_{1/2}$ = 81.3 Myr) in various geological archives...
The Qinghai-Tibet Plateau is simultaneously influenced by the westerlies and the Asian monsoon, and the variations in monsoon moisture have significant impacts on the entire Qinghai-Tibet Plateau and Asian climate system. Among the interesting tracers of atmospheric circulation, the Be-10 isotope deposited in soils can be a potential one. The dominant atmospheric production, relatively long...
Wetlands are the largest carbon storage in the tundra zone of the Tibetan Plateau (amsl >4500 m), and the stored carbon is highly vulnerable to global warming. We selected two major wetland types in northern Tibet, lacustrine wetland (NC) and intermountain wetlands (NB), and took one soil profile each for soil organic carbon (SOC) content and carbon isotopes (δ13C & 14C) analysis. The results...
Abstract: To overcome the disadvantages of manual purification system during AMS-14C measurement, including inefficiency, unstable quality of graphite, and interference from modern carbon. CAGS-IHEG (Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences) introduced AGE-3 to improve the performance of small carbon graphite, leading to the rapid production...
Competitive AMS measurements of $^{26}$Al are possible at low ion energies. Selecting Al$^-$ as a negative ion for the tandem accelerator has the benefit of the complete suppression of the interfering isobar $^{26}$Mg. However, because of the notoriously low yield of Al$^-$ from a Cs sputter ion source, we have to pull out all the stops to improve the overall efficiency, in particular the...
The age of a small plant leaf frozen in ground ice at a depth of 8.3 meters in a borehole on the summit area of Mt. Goshiki in the Daisetsu Mountains, Hokkaido, Japan, was determined using radiocarbon dating. The calibrated age of the leaf (using OxCal v. 4.4.4) was 288±26 (40.0%) or 182±39 (48.2%) calendar years BP, placing it within the last Little Ice Age in Japan. This age indicates the...
Dissolved organic carbon (DOC) is a major, yet little understood component of the global carbon cycle. Although radiocarbon analysis of DOC provides valuable information on the origin and age of this pool, the number of measurements, particularly in marine systems, is limited by the complexity and low efficiency of existing methods. These methods generally use UV irradiation to oxidize the...
Simple gas ionization chamber design for low-energy ion measurements
Shulin Shi 1, Hongtao Shen 1、2* , Junsen Tang 1, Li Wang 1, Guofeng Zhang 1, Dingxing Chen 1, Linjie Qi 1, Yun He1、2,Ning Wang1、2, Qingzhang Zhao3, Ming He3, Shan Jiang3
1. College of Physics and Technology, Guangxi Normal University, Guilin Guangxi 541004, China
2．Guangxi Key Laboratory of Nuclear Physics and Nuclear...
Oil sands (also tar sands) are a type of unconventional petroleum deposit from which bitumen is mined by surface mining or in-situ extraction to produce heavy oil. A globally significant soil sand region (producing 3.3 M barrels per day in 2022), is located in the Athabasca River basin of Alberta, Canada. The environmental impacts of oil sand mining, specifically air pollution, are not well...
Polycyclic aromatic hydrocarbons (PAHs) form one of the most important classes of persistent pollutants (Blumer 1976). Some PAHs are carcinogenic and mutagenic. Owing to their adverse effect on human/ecological health and widespread distribution around in the environment, identification of the sources of PAHs is of special concern (Pedersen et al. 2004). Thus, elucidating and evaluating the...
Identifying the sources of atmospheric Carbon dioxide (CO2) is an important prerequisite for developing effective mitigation strategies. Here we conducted regular observations of the atmospheric CO2 mixing ratio and its carbon isotope compositions (i.e., Δ14C and δ13C) in Xi'an and Beijing during winter, to estimate source contributions of CO2 emissions in Chinese megacities. The results...
Air at different heights within 2000 m at the northern foot of the Qinling Mountains were sampled by unmanned aerial vehicle to study the vertical variations and sources of atmospheric CO2 and 14CO2. The CO2 concentrations mainly exhibited a slight decreasing trend with increasing height during summer observations, which was in contrast to the increasing trend that was followed by a subsequent...
Uranium-236 serves as a widely utilized analytical tool for detecting environmental radioactive contamination and tracking natural processes. Given the low concentration of 236U in environmental samples, Accelerator Mass Spectrometry (AMS) emerges as a highly sensitive mass spectrometry method. Based on the AMS system at Guangxi Normal University (GXNU-AMS), we have developed and evaluated a...
The measurement of tritium by accelerator mass spectrometry (AMS) is a precise technique for determining tritium content. This technology is characterized by small sampling, high accuracy, and selectivity, making it a favorable method for measuring tritium in solids. In the process of measuring tritium by AMS, it is necessary to prepare the tritium-containing sample into the chemical form of...
Located within the Bataan volcanic arc of the Philippines is the potentially active Natib Volcano, situated on the western flank of Luzon Island near a decommissioned Bataan nuclear power plant (BNPP). As the Philippine government explores nuclear power as part of its energy mix, attention has shifted towards repurposing the former BNPP. However, despite its classification as potentially...
We applied the high temperature pyrolysis-combustion technique to 2 last glacial loess-paleosol sequences in the Chinese Loess Plateau (CLP) to partition the total soil organic carbon (SOC) into pyrolysis labile-recalcitrant and pyrolysis inert SOC fractions for accelerator mass spectrometry radiocarbon (AMS 14C) dating analysis to explore which SOC fraction yields more reliable AMS 14C...
Groundwater, the world's critical freshwater resource, is currently facing significant challenges from overexploitation and depletion, particularly on small islands such as Tongatapu in the Kingdom of Tonga. This study aimed to analyze the groundwater system of the island by integrating radiocarbon dating and water quality analysis. Groundwater samples were collected from coastal areas and...
The background value of 10Be/9Be in 1MV AMS was originally ~10-14, so the use was limited for the measurement of low-value Be samples. Therefore, we started research to lower the background value without significantly changing the existing equipment itself. First, a sample with a low background value was obtained. Next, various attempts were made on the existing equipment to increase the...
Atmospheric nuclear weapons tests caused a dramatic increase of atmospheric 14CO2 with a peak around 1964, thereafter, bomb 14C became a powerful tool for dating recent carbonaceous material. There are lots of observational atmospheric 14CO2 records and reconstructed 14CO2 records based on annual tree rings covered bomb peak in the world, and they were compiled by Hua et al. in 2022. In China,...
129I is a long-lived nuclide with very low nature level, but the presence of 129I in the environment has changed significantly since the beginning of the nuclear era. Accelerator mass spectrometer (AMS) is the most sensitive method for 129I measurement, which is widely used in environmental monitoring, geological evolution dating, nuclear activities tracking and other fields. For further...
A 1MV AMS was installed at IHEG-CAGS in 2023. We usually measure 14C at charge state 2+ because beam transmission yield reaches maximum value at a terminal voltage of 1000 kV. However, when 2+ ions are used for the 1MV 14C analysis, interference by the 7Li2 molecular ions is severe in some cases. Therefore, it was necessary to investigate the source of Li interference.
Herein, we give some...
The 10Be record from the Northern Greenland NEEM ice core has been found to significantly correlate with the mid-latitude tropopause pressure on both seasonal and annual scales, highlighting the potential of applying ice core 10Be records to study the past stratosphere-troposphere exchange at mid-latitudes. However, a comprehensive study is required to determine if this relationship holds for...
Advances in Accelerator Mass Spectrometry (AMS) have made palaeoclimate reconstructions using meteoric cosmogenic nuclides available for a wide range of environments, including ocean, lake and ice cores (Raisbeck et al., 2007; Yokoyama et al., 2016; Behrens et al., 2022). Here, we report a Be-10 record for the past 45,000 years using sediments from Lake Biwa, the largest lake in Japan. The...
Introduction: Cl is a volatile element and can be lost during formation and evolution of planetary bodies, which can lead to fractionation of its two stable isotopes, 35Cl and 37Cl. Stable Cl isotope variations (reported as δ37Cl, in parts per thousand (‰), relative to standard mean ocean chloride (SMOC) [1]) have been measured in many lunar samples and have produced a wide range from -4‰ to...
- Introduction
Radiocarbon Laboratory of Henan University was primitively established in 2017, and introduced a compact accelerator mass spectrometer (AMS) – a 200 KV mini carbon dating system (MICADAS) in 2023, which had greatly improved the testing capacity of the laboratory. Here we present the performance of MICADAS.
The laboratory can accurately measure the weight of the sample through...
The extractions of beryllium and aluminum samples by ion exchange resins prior AMS, depend heavily on the quality of quartz purity. However, even with meticulous purification, objectives to guarantee sufficient AMS current are not always achieved.
Using a well-known natural sample that had already been studied and purified, quantitative multi-elements (B, Be, Al, Ti, Ca, Na, K, Mg, Fe)...
The correction of " Reservoir Effect" in lake sediments is a particularly challenging issue in radiocarbon chronology. The controlling factors of Reservoir Effect and how to correct for it remain unclear. A research team systematically reviewed the past 20 years of lake studies in different climatic regions of China, and systematically investigated the 14C ages and correction methods used in...
Uranium mining and milling activities contribute to the release of natural uranium and its decay products into the environment. This may lead to potential radiological risks. While U-238 and its decay products are routinely monitored, the behaviour of the U-235 decay products is either not considered, or only estimated based on the U-238 decay chain in radiological assessments [1].
Pa-231 is...
In situ radiocarbon（14C）is produced within minerals at the earth’s surface by a number of spallation reactions. Due to its relatively short half-life of 5730 years, it serves as a unique cosmogenic nuclide tool for the measurement of measuring rapid erosion rates (>10–3 cm yr–1) and events occurring over the past 25,000 years. At Xi'an AMS Center, we have developed and constructed a new vacuum...
The Tibetan Plateau and its surrounding mountains (TPSM) has experienced glacier expansion during the Global Last Glacial Maximum and punctuated retreat during the following deglaciation. Preserved moraines provide a reliable record for glacier extent and their terrestrial cosmogenic exposure dating marks the transition of glacial advance or stasis to one of recession. As a wide geographic...
Radiocarbon (14C) dating of the total organic carbon (TOC) content of lacustrine sediments is usually affected by a 14C reservoir effect and the 14C dates are often systematically older than the true ages, due to the input of carbon from different sources. Therefore, when using TOC's radiocarbon data to build the age-depth relation, it is necessary to accurately deduct the radiocarbon...
The Rafter Radiocarbon Lab, through the CarbonWatch-Urban project, is developing detailed CO2 emissions information for all towns and cities in New Zealand. Tracking fossil fuel CO2 emissions traditionally involves radiocarbon measurements of atmospheric CO₂ to separate fossil fuel from natural CO2 fluxes. In contrast, this study aims to further separate CO2 and carbon monoxide (CO) from wood...
The purpose of this study is to establish a method for extracting charcoal from inside pottery and measuring its radiocarbon date. We proposed a new method that uses X-ray equipment to search for carbonised grains embedded within earthenware and directly date these grains in relation to grain cultivation in the Japanese archipelago [1]. This method allows us to obtain data on the introduction...
The development of the AMS 14C dating preparation laboratory has been completed in the Beijing Normal University (BNU). There are 2 lines of home-made CO2 generation vacuum systems and 4 lines of home-made graphitization vacuum systems. For CO2 generation, a pyrolysis-combustion vacuum system with an infrared gas analyzer, ultrapure O2 and Ar gas supply systems, a manometer with a pressure...
In this paper we revisit cosmogenic nuclide analysis from multilevel karst system in Atapuerca mountain range to discuss difficulty and complexity in interpretating cosmogenic data not only for chronology but also for sediment dynamics, i.e., provenance, transport pathway and depositional processes. Atapuerca is situated in the western end of Europe, and is among the key sites in the study of...
Understanding the sources and fluxes of dissolved inorganic carbon (DIC) in karst reservoirs is essential for regional carbon cycling studies, particularly concerning the "karst effect". This study utilized dual carbon isotopes (δ13CDIC and Δ14CDIC) to estimate the contribution rates and input fluxes of DIC from various sources in the Aha Reservoir (AHR), located in southwestern China. Our...
Atmospheric aerosols have serious impacts on the Earth’s climate system directly by scattering and absorbing solar radiation and indirectly by acting as cloud condensation nuclei. They also cause adverse effects on human health and play an important role in atmospheric chemistry. Although carbonaceous aerosols that represent a large fraction of fine aerosol mass have been extensively studied,...
The atmospheric concentration of carbon dioxide (CO$_{2}$) has been increasing steadily since industrialization. Emission of $^{14}$C-free CO$_{2}$ from the combustion of fossil fuels, such as coal, oil or gas, reduces the $^{14}$CO$_{2}$ to $^{12}$CO$_{2}$ ratio in the atmosphere. When the background $^{14}$CO$_{2}$ level is known, the local surplus of fossil CO$_{2}$ can be calculated using...
Suppression of isobars for AMS profits from studying element selective interactions of slow ions with photons or in collisions with other atoms. Negative ions extracted from an ion source can be slowed down to near-thermal energies in an ion cooler consisting of a buffer gas filled radio-frequency quadrupole. The slow ions collide with the buffer gas and can be overlapped with a laser beam....
Abstract: Accelerator Mass Spectrometry (AMS) is considered to be the ultra-sensitivity technique for 14C isotope analysis at present, however, high-quality 14C data are heavily dependent on the sample graphitization. Relying on AGE-3 from Ionplus, the graphitization process not only improves the sample processing efficiency but also reduces the sampling cost compared to the traditional...
Monitoring the fluctuations of radiocarbon in environmental samples (air, biological, groundwater, etc.) around nuclear facilities is a commonly used tool to assess the safe operation of the facility. Measurements of radiocarbon in environmental monitoring programs around the nuclear facility are primarily performed using liquid scintillation counters, which are known to be capable of...
Beloe Lake (51°17’40” N, 82°38’50” E, 530 m a.s.l.) is a foothill lake in the northwestern Altai of Russia. Twenty-five AMS 14C dates on sedimentary TOC and plant remaining samples were obtained from a 193-cm long core to construct the chronology of the lake sediment sequence. Additionally, 210Pb and 137Cs dating were applied to the uppermost 20 cm sediments of the core to complement the...
Calcium is a major element in the biosphere and lithosphere. Its cosmogenic isotope 41Ca, with a half-life of 99 thousand years1, can trace environmental processes at an age scale beyond the reach of 14C.
Here,we achieved the analysis of 41Ca in environmental samples using ATTA, and a single analysis requires 80mg of metallic calcium. In addition, we have developed a process for preparing...
For nearly three decades, the Centre for Accelerator Science at ANSTO has been conducting radiocarbon analyses using solid sample ion sources. To accommodate smaller samples, we developed both Laser Heated Furnaces (LHFs) and Micro-Conventional Furnaces (MCFs) over a decade ago. These innovations have significantly expanded our capabilities, enabling the analysis of samples containing as...
Since the acceptance of the 5MV AMS ASTER (CEREGE, Aix en Provence), the national laboratory LN2C is routinely measuring 10Be and 26Al for the scientific community. Previously based on a solvent extraction using EDTA and CCl4, we moved in 2008 due to the end of CCl4 production and to change for a safer chemistry, to a separation by ion exchange chromatography using anionic and cationic resins....
Iodine, as an essential biophilic element, is widely present in living organisms and crucial for human life activities. Among iodine isotopes, only iodine-127 is a stable nucleus, while iodine-129 has the longest half-life (1570 million years). Therefore, it is particularly important to isolate iodine from soil samples and utilize AMS to measure the ratio of iodine-129 to iodine-127 for...
