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  • 11
    Publication Date: 2022-05-25
    Description: Author Posting. © Arizona Board of Regents on behalf of the University of Arizona, 2010. This article is posted here by permission of Dept. of Geosciences, University of Arizona for personal use, not for redistribution. The definitive version was published in Radiocarbon 52 (2010): 727-734.
    Description: In 2008, a large African baobab (Adansonia digitata L.) from Makulu Makete, South Africa, split vertically into 2 sections, revealing a large enclosed cavity. Several wood samples collected from the cavity were processed and radiocarbon dated by accelerator mass spectrometry (AMS) for determining the age and growth rate dynamics of the tree. The 14C date of the oldest sample was found to be of 1016 ± 22 BP, which corresponds to a calibrated age of 1000 ± 15 yr. Thus, the Makulu Makete tree, which eventually collapsed to the ground and died, becomes the second oldest African baobab dated accurately to at least 1000 yr. The conventional growth rate of the trunk, estimated by the radial increase, declined gradually over its life cycle. However, the growth rate expressed more adequately by the cross-sectional area increase and by the volume increase accelerated up to the age of 650 yr and remained almost constant over the past 450 yr.
    Description: This material is based on work supported by a grant from the Romanian National University Research Council (PN II - IDEI 2354 Nr. 1092) and by US National Science Foundation under Cooperative Agreement OCE-022828996.
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 12
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 294 (2013): 296-299, doi:10.1016/j.nimb.2011.10.016.
    Description: The National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility at the Woods Hole Oceanographic Institution has developed an Accelerator Mass Spectrometry (AMS) system designed specifically for the analysis of 14C in a continuously flowing stream of carrier gas. A key part of the system is a gas-accepting microwave ion source. Recently, substantial progress has been made in the development of this source, having achieved ion currents rivaling that of a traditional graphite source (albeit at relatively low efficiency). Details and present performance of the gas source are given. Additionally, representative results obtained from coupling the source to both a gas chromatograph and gas bench are presented.
    Description: This work is supported by a Cooperative Agreement (OCE- 2310753487) with the US National Science Foundation.
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 13
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of American Institute of Physics for personal use, not for redistribution. The definitive version was published in Review of Scientific Instruments 83 (2012): 02B304, doi:10.1063/1.3656408.
    Description: A 2.45 GHz microwave ion source coupled with a magnesium charge exchange canal (CxC) has been successfully adapted to a large acceptance radiocarbon accelerator mass spectrometry system at the National Ocean Sciences AMS Facility (NOSAMS), Woods Hole Oceanographic Institution. CO2 samples from various preparation sources are injected into the source through a glass capillary at 370 µl/min. Routine system parameters are about 120 - 140 µA of negative 12C current after the CxC, leading to about 400 14C counts per second for a modern sample and implying a system efficiency of 0.2%. While these parameters already allow us to perform high quality AMS analyses on large samples, we are working on ways to improve the output of the ion source regarding emittance and efficiency. Modeling calculations suggest modifications in the extraction triode geometry, shape and size of the plasma chamber could improve emittance and hence ion transport efficiency. Results of experimental tests of these modifications are presented.
    Description: This work has been supported by the US National Science Foundation through Cooperative Agreement OCE-0753487.
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 14
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 269 (2011): 3176–3179, doi:10.1016/j.nimb.2011.04.019.
    Description: In 2007 we published the design of a novel accelerator mass spectrometry (AMS) system capable of analyzing gaseous samples injected continuously into a microwave plasma gas ion source. Obvious advantages of such a system are drastically reduced processing times and avoidance of potentially contaminating chemical preparation steps. Another paper in these proceedings will present the progress with the development of the microwave gas ion source that has since been built and tested at the National Ocean Sciences AMS Facility in Woods Hole. In this paper we will review the original design and present updates, reflecting our recent encouraging experience with the system. A simple summary: large acceptance ion beam optics design is beneficial to accelerator mass spectrometry in general, but essential to AMS with plasma gas ion sources.
    Keywords: Ion optics ; Computer modeling ; Microwave ion source ; Continuous-flow AMS
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 15
    Publication Date: 2022-05-25
    Description: © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS ONE 10 (2015): e0117193, doi:10.1371/journal.pone.0117193.
    Description: The article reports the radiocarbon investigation results of the Lebombo Eco Trail tree, a representative African baobab from Mozambique. Several wood samples collected from the large inner cavity and from the outer part of the tree were investigated by AMS radiocarbon dating. According to dating results, the age values of all samples increase from the sampling point with the distance into the wood. For samples collected from the cavity walls, the increase of age values with the distance into the wood (up to a point of maximum age) represents a major anomaly. The only realistic explanation for this anomaly is that such inner cavities are, in fact, natural empty spaces between several fused stems disposed in a ring-shaped structure. We named them false cavities. Several important differences between normal cavities and false cavities are presented. Eventually, we dated other African baobabs with false inner cavities. We found that this new architecture enables baobabs to reach large sizes and old ages. The radiocarbon date of the oldest sample was 1425 ± 24 BP, which corresponds to a calibrated age of 1355 ± 15 yr. The dating results also show that the Lebombo baobab consists of five fused stems, with ages between 900 and 1400 years; these five stems build the complete ring. The ring and the false cavity closed 800–900 years ago. The results also indicate that the stems stopped growing toward the false cavity over the past 500 years.
    Description: The research was fully funded by the Romanian Ministry of National Education CNCS-UEFISCDI under grant PN-II-ID-PCE-2013-76.
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 16
    Publication Date: 2022-05-25
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 11 (2016): e0146977, doi:10.1371/journal.pone.0146977 .
    Description: The article reports the radiocarbon investigation of Anzapalivoro, the largest za baobab (Adansonia za) specimen of Madagascar and of another za, namely the Big cistern baobab. Several wood samples collected from the large inner cavity and from the outer part/exterior of the tree were investigated by AMS (accelerator mass spectrometry) radiocarbon dating. For samples collected from the cavity walls, the age values increase with the distance into the wood up to a point of maximum age, after which the values decrease toward the outer part. This anomaly of age sequences indicates that the inner cavity of Anzapalivoro is a false cavity, practically an empty space between several fused stems disposed in a ring-shaped structure. The radiocarbon date of the oldest sample was 780 ± 30 bp, which corresponds to a calibrated age of around 735 yr. Dating results indicate that Anzapalivoro has a closed ring-shaped structure, which consists of 5 fused stems that close a false cavity. The oldest part of the biggest za baobab has a calculated age of 900 years. We also disclose results of the investigation of a second za baobab, the Big cistern baobab, which was hollowed out for water storage. This specimen, which consists of 4 fused stems, was found to be around 260 years old.
    Repository Name: Woods Hole Open Access Server
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  • 17
    Publication Date: 2022-05-25
    Description: Author Posting. © Studia Chemia, 2018. Studia Universitatis Babes-Bolyai Seria Chemia is an Open Access Journal (read, download, copy, distribute, print for research use, search, or link to the full texts of articles). The definitive version was published in Studia Universitatis Babes-Bolyai, Seria Chemia 63, no. 3 (2018): 41-48, doi:10.24193/subbchem.2018.3.03.
    Description: The article reports the AMS (accelerator mass spectrometry) radiocarbon investigation results of the old common ash of Aiton. Five wood samples were collected from the trunk of the tree. The deepest ends of the samples were analysed by AMS radiocarbon. We found radiocarbon dates between 165 ± 20 BP and 240 ± 18 BP, which correspond to calibrated ages of 230 – 360 years. These results, combined with a ring counting estimate, indicate an age of 330 ± 30 years for the ash of Aiton. By this value, the ash of Aiton becomes the oldest known common ash with accurate dating results.
    Description: The research was funded by the Romanian Ministry of Research and Innovation CNCS-UEFISCDI under grant PN-III-P4-ID-PCE-2016-0776, Nr. 90/2017.
    Keywords: AMS radiocarbon dating ; Fraxinus excelsior ; Dendrochronology ; Age determination
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 18
    Publication Date: 2022-10-26
    Description: Author Posting. © Studia Chemia, 2021. This article is posted here by permission of Studia Chemia for personal use, not for redistribution. The definitive version was published in Studia Universitatis Babes: Bolyai Chemia, 66(1), 153-163, http://dx.doi.org/10.24193/subbchem.2021.01.12.
    Description: The article reports the AMS (accelerator mass spectrometry) radiocarbon dating results of the Big baobab of Outapi, which is the largest African baobab of Outapi, Namibia. The investigation of this monumental baobab revealed that it consists of 8 fused stems, out of which 4 are false stems. The Big baobab exhibits a closed ring-shaped structure. Three stems build the ring, which is now incomplete due to previous damage to the false cavity. Three wood samples were collected from the false cavity and from the longest false stem. Seven segments were extracted from the samples and dated by radiocarbon. The oldest investigated sample segment had a radiocarbon date of 820 ± 17 BP, corresponding to a calibrated age of 780 ± 10 calendar years. According to dating results, the Big baobab of Outapi is 850 ± 50 years old.
    Description: The investigation and sampling of the baobab was authorized by the Ministry of Environment and Tourism of Namibia under the Research/Collecting Permit No. 1934_2014. The research was funded by the Romanian Ministry of Education and Research CNCS-UEFISCDI under grant PN-III-P4-ID-PCE-2020-2567, No. 145/2021.
    Keywords: AMS radiocarbon dating ; Adansonia digitata ; Dendrochronology ; Age determination ; False cavity ; Multiple stems
    Repository Name: Woods Hole Open Access Server
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  • 19
    Publication Date: 2022-10-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Patrut, R. T., Patrut, A., Rakosy, D., Rakosy, L., Lowy, D. A., Von Redenf, K. F., & Bodis, J. Radiocarbon dating of Makuri Le boom, a very old African baobab from Nyae Nyae, Namibia. Studia Universitatis Babes-Bolyai Chemia, 65(2), (2020): 149-159, doi:10.24193/subbchem.2020.2.12.
    Description: The article reports the AMS (accelerator mass spectrometry) radiocarbon dating results of Makuri Lê boom, a very large African baobab from Nyae Nyae Conservancy, Namibia. The investigation of this superlative baobab shows that it consists of 12 independent stems of different dimensions, which belong to three generations. Makuri Lê boom has an open ring-shaped structure, a type of architecture which allows baobabs to reach very large sizes and old ages. The oldest sample has a radiocarbon date of 1602 ± 17 BP, which corresponds to a calibrated age of 1520 ± 35 calendar yr. By this value, Makuri Lê boom becomes one of the oldest dated baobabs and angiosperms with accurate dating results.
    Description: The research was funded by the Romanian Ministry of National Education CNCS-UEFISCDI under grant PN-III-P4-ID-PCE-2016-0776, Nr. 90/2017.
    Keywords: AMS radiocarbon dating ; Adansonia digitata ; Tropical trees ; Dendrochronology ; Age determination ; Multiple stems
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 20
    Publication Date: 2022-10-26
    Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Patrut,Roxana T.; Patrut,Adrian; Pock-Tsy,Jean-Michel Leong; Woodborne,Stephan; Rakosy,Laszlo; Danthu,Pascal; Ratiu,Ileana-Andreea; Bodis,Jeno; Von Reden,Karl. Radiocarbon investigation of a superlative Grandidier Baobab, the Big Reniala of Isosa. Studia Universitatis Babes-Bolyai Chemia, 64(4), (2019): 131-139, doi:10.24193/subbchem.2019.4.10.
    Description: The article discloses the accelerator mass spectrometry (AMS) radiocarbon dating results of the Big Reniala of Isosa, which is a massive Grandidier baobab (Adansonia grandidieri Baill.) of Madagascar. The investigation of this baobab shows that it consists of 5 perfectly fused stems and exhibits a cluster structure. The calculated wood volume of the tree is 540 m3, which makes the Big Reniala of Isosa the largest individual of all Adansonia species and also the biggest known angiosperm in terms of volume. Several samples were collected from the outer part of the stems. The oldest dated sample had a radiocarbon date of 934 ± 24 BP, which corresponds to a calibrated age of 845 ± 25 years. This value indicates an age of 1000 ± 100 years for the big Reniala of Isosa.
    Description: The investigation and sampling of the baobab was authorised by the Forestry Direction of the Ministry of Environment, Ecology and Forestry of Madagascar and by the Madagascar National Parks. The research was funded by the Romanian Ministry of National Education CNCS-UEFISCDI under grant PN-III-P4-ID-PCE-2016-0776, No. 90/2017.
    Keywords: AMS radiocarbon dating ; Adansonia grandidieri ; Tropical trees ; Multiple stems
    Repository Name: Woods Hole Open Access Server
    Type: Article
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