von Reden Karl F.

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von Reden

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Karl F.

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African baobabs with double closed ring-shaped structures and two separate false cavities : radiocarbon investigation of the baobab of Golconda Fort

(Studia Chemia, 2016) Patrut, Adrian ; Patrut, Roxana T. ; Rakosy, Laszlo ; Bodis, Jeno ; Lowy, Daniel A. ; Forizs, Edit ; von Reden, Karl F.

The article discloses the results of radiocarbon investigation of the baobab of Golconda Fort, Hyderābād, India, which is the largest African baobab outside Africa. Two wood samples were collected from the large inner cavity; of these we extracted several segments for AMS (accelerator mass spectrometry) radiocarbon dating. The oldest sample segment had a radiocarbon date of 342 ± 22 BP, which corresponds to a calibrated age of 430 ± 20 yr. We estimate that the oldest part of the baobab has an age of 475 ± 50 yr. The investigation of the baobab of Golconda Fort revealed that it consists of 6 + 2 fused stems. Six stems build two rings that close two distinct false cavities, while two additional stems are located outside the rings. We called this new type of architecture double closed ring-shaped structure with two separate false cavities.
Radiocarbon dating of Makuri Le boom, a very old African baobab from Nyae Nyae, Namibia

(Department of Chemistry, 2020) Patrut, Roxana T. ; Patrut, Adrian ; Rakosy, Demetra ; Rakosy, Laszlo ; Lowy, Daniel A. ; Bodis, Jeno ; von Reden, Karl F.

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.
The Keck Carbon Cycle AMS Laboratory, University of California, Irvine : status report

(Dept. of Geosciences, University of Arizona, 2010-08) Beverly, Robert K. ; Beaumont, Will ; Tauz, Denis ; Ormsby, Kaelyn M. ; von Reden, Karl F. ; Santos, Guaciara M. ; Southon, John R.

We present a status report of the accelerator mass spectrometry (AMS) facility at the University of California, Irvine, USA. Recent spectrometer upgrades and repairs are discussed. Modifications to preparation laboratory procedures designed to improve sample throughput efficiency while maintaining precision of 2–3‰ for 1-mg samples (Santos et al. 2007c) are presented.
Radiocarbon investigation of the big baobab of Outapi, Namibia

(Studia Chemia, 2021-03-31) Patrut, Adrian ; Patrut, Roxana T. ; Rakosy, Laszlo ; Rakosy, Demetra ; Ratiu, Ileana-Andreea ; von Reden, Karl F.

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.
Radiocarbon investigation of two old elms from Romania

(Studia Chemia, 2022-03) Patrut, Adrian ; Patrut, Roxana T. ; Bocos-Bintintan, Victor ; Ratiu, Ileana-Andreea ; Rakosy, Laszlo ; Zdrob, George ; Vanca, Eufrosina ; von Reden, Karl F.

The paper reports the AMS (accelerator mass spectrometry) radiocarbon investigation results of two superlative elms from Romana, the very large field elm of Calafat, with a wood volume of 85 m 3 , and the wych elm of Sadova. Two wood samples were extracted from each elm and were analysed by AMS radiocarbon. The oldest dated sample from the elm of Calafat had a radiocarbon date of 350 ± 19 BP, which corresponds to a calibrated age of 415 ± 25 years, while the oldest sample from the elm of Sadova had a radiocarbon date of 188 ± 24 BP, corresponding to a calibrated age of 260 ± 25 years. These values indicate high ages for the two elms, namely 430 ± 25 years or the elm of Calafat and 400 ± 25 years for the elm of Sadova.
Progress with a gas-accepting ion source for Accelerator Mass Spectrometry

( 2010-08) Roberts, Mark L. ; von Reden, Karl F. ; McIntyre, Cameron P. ; Burton, Joshua R.

The National Ocean Sciences AMS (NOSAMS) facility at Woods Hole Oceanographic Institution has developed a novel, gas-accepting microwave-plasma ion-source. The source is a key component of a compact Accelerator Mass Spectrometry (AMS) system built for the analysis of 14C in a continuously flowing gas stream. The gas source produces carbon currents from a stream of CO2 with currents typical of a traditional graphite source. Details of the gas source, including ion current achieved, optimal flow rate, efficiency, and memory are presented. Additionally, data obtained from coupling a gas chromatograph to the source to will be shown.
Radiocarbon investigation of the Superlative African Baobabs from Savé Valley Conservancy, Zimbabwe

(Universitatis Babes-Bolyai, Department of Chemistry, 2019) Patrut, Adrian ; Patrut, Roxana T. ; Rakosy, Laszlo ; Lowy, Daniel A. ; Margineanu, Dragos ; von Reden, Karl F.

The article reports the radiocarbon investigation results of the superlative African baobabs from Savé Valley, Zimbabwe. Several wood samples collected from these baobab were analysed by AMS (accelerator mass spectrometry) radiocarbon dating. The radiocarbon dates of the oldest samples were 1529 ± 14 BP for Matendere Big baobab, 1179 ± 19 BP for Chishakwe Big tree and 1096 ± 35 BP for Mokore Giant baobab. The corresponding calibrated ages are 1430 ± 15, 1090 ± 40 and 1020 ± 25 calendar yr. The oldest tree from Savé Valley, which we described previously, is the Humani Bedford Old baobab. The radiocarbon date of its oldest sample, 1655 ± 14 BP, corresponds to a calibrated age of 1580 ± 30 calendar yr.
Radiocarbon investigation of the pedunculate oak of Botosana, Romania

(Studia Chemia, 2018) Patrut, Adrian ; Robu, Nicolae ; Savu, Vasile ; Patrut, Roxana T. ; Rakosky, Laszlo ; Ratiu, Ileana-Andreea ; Lowy, Daniel A. ; Margineanu, Dragos ; von Reden, Karl F.

The article discloses the AMS (accelerator mass spectrometry) radiocarbon dating results of the pedunculate oak of Botoşana. Four wood samples were extracted from its trunk. Five segments extracted from these samples were analyzed by AMS radiocarbon. Their radiocarbon dates were found to be between 161 ± 21 BP and 260 ± 20 BP. These values correspond to calibrated ages of 235 – 365 years. The dating results extrapolated to the geometric center of the trunk indicate an age of 645 ± 50 years for the oak of Botoşana.
Design and reality : continuous-flow accelerator mass spectrometry (CFAMS)

( 2010-09) von Reden, Karl F. ; Roberts, Mark L. ; McIntyre, Cameron P. ; Burton, Joshua R.

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.
Fire history of a giant African baobab evinced by radiocarbon dating

(Dept. of Geosciences, University of Arizona, 2010-08) Patrut, Adrian ; Mayne, Diana H. ; von Reden, Karl F. ; Lowy, Daniel A. ; Van Pelt, Robert ; McNichol, Ann P. ; Roberts, Mark L. ; Margineanu, Dragos

The article reports the first radiocarbon dating of a live African baobab (Adansonia digitata L.), by investigating wood samples collected from 2 inner cavities of the very large 2-stemmed Platland tree of South Africa. Some 16 segments extracted from determined positions of the samples, which correspond to a depth of up to 15–20 cm in the wood, were processed and analyzed by accelerator mass spectrometry (AMS). Calibrated ages of segments are not correlated with their positions in the stems of the tree. Dating results indicate that the segments originate from new growth layers, with a thickness of several centimeters, which cover the original old wood. Four new growth layers were dated before the reference year AD 1950 and 2 layers were dated post-AD 1950, in the post-bomb period. Formation of these layers was triggered by major damage inside the cavities. Fire episodes are the only possible explanation for such successive major wounds over large areas or over the entire area of the inner cavities of the Platland tree, able to trigger regrowth.
Optimizing a microwave gas ion source for continuous-flow accelerator mass spectrometry

( 2011-09) von Reden, Karl F. ; Roberts, Mark L. ; Burton, Joshua R. ; Beaupre, Steven R.

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.
African baobabs with a very large number of stems and false stems : radiocarbon Investigation of the baobab of Warang

(Studia Chemia, 2017-03) Patrut, Adrian ; Garnaud, Sébastien ; Ka, Oumar ; Patrut, Roxana T. ; Diagne, Tomas ; Lowy, Daniel A. ; Forizs, Edit ; Bodis, Jeno ; von Reden, Karl F.

The article presents the AMS (accelerator mass spectrometry) radiocarbon dating results of the baobab of Warang, Senegal. The investigation of the baobab revealed that it consists of 18 partially fused stems, which represents the largest number of stems reported for an African baobab. Three stems build the ring that closes a false cavity, while 15 stems grow outside the ring. Seven wood samples were collected from the false cavity and from the outer part of other stems. The dating results evinced that the stems belong to four different generations, out of which the first generation is around 500 years old. We also documented the presence of false stems, which emerge from a large adjacent stem, are triangular in horizontal section and act as an anchor. The baobab of Warang possesses 12 ordinary stems and 6 false stems.
Future of the NOSAMS Tandetron AMS system

( 2009-04-13) von Reden, Karl F.

The NOSAMS 3 MV Tandetron AMS system will soon reach its 20th anniversary of operation. A critical review of all aspects of the system is necessary to assess the analytical, economic, and operational factors that enter into the consideration of either an upgrade or a replacement of the instrument. Recent in‐house experience with the design and construction of a large‐acceptance 14C AMS system gives us a benchmark with which to compare the expected outcome of an upgrade. The present ion analysis efficiency of our Tandetron system is roughly 1%, well below the 4% value of our new system. This affects the lower limit of analyzable sample size, speed of analysis, exposure to systematic errors, and the upper limit of achievable single‐sample counting statistics. At first glance it may seem obvious that a replacement (even at higher cost) would be preferable to an upgrade. However, it will be shown that there are good reasons to consider the latter. One of the most compelling is the fact that the Tandetron is a state‐of‐the‐art and superior high‐current accelerator design with minimal signs of aging and very low maintenance. Ion beam modeling calculations show that the main transmission limitation of the instrument is caused by the design of our injector, a four‐magnet “Recombinator”, making it difficult to perform reliable AMS with negative currents exceeding 80 μA. To be acceptable, an upgrade should bring the Tandetron to at least 3% ion efficiency by replacing the injector with a properly matched high‐transmission device.
Radiocarbon investigation of two large african baobabs from Kizimkazi, Zanzibar, Tanzania

(Studia Chemia, 2022-06) Adrian, Patrut ; Roxana T., Patrut ; Laszlo, Rakosy ; Ileana-Andreea, Ratiu ; Jenö, Bodis ; Nassor Mahmoud, Nassor ; Karl F., Von Reden

The article reports the AMS (accelerator mass spectrometry) radiocarbon dating results of Kizimkazi Big tree and Kizimkazi II baobab, two large African baobabs from Zanzibar, Tanzania. Unfortunately, both baobabs toppled and died in 2018 and 2020, during violent storms. The investigation of the two baobabs evinced that the first of them, which was also the biggest tree of Tanzania, consisted of 5 stems, out of which 2 were false ones, and had a closed ring-shaped structure. The second baobab was composed of 4 fused stems and had a cluster structure. Several wood samples were collected from the two baobabs. Seven segments were extracted from the samples and dated by radiocarbon. The oldest segment from Kizimkazi Big tree had a radiocarbon date of 312 ± 18 BP, corresponding to a calibrated age of 380 ± 10 calendar years. According to dating results, the Kizimkazi Big tree died at the age of 400 ± 25 years. The oldest segment from Kizimkazi II baobab had a radiocarbon date of 137 ± 17 BP, corresponding to a calibrated age of 190 ± 10 calendar years. This value indicates that the Kizimkazi II baobab was 250 ± 25 years old when it died.
Radiocarbon dating of a very old African baobab from Savé Valley, Zimbabwe

(Studia Chemia, 2016) Patrut, Adrian ; Rakosy, Laszlo ; Patrut, Roxana T. ; Ratiu, Ileana ; Forizs, Edit ; Lowy, Daniel A. ; Margineanu, Dragos ; von Reden, Karl F.

The article reports the radiocarbon investigation results of the Humani Bedford baobab, an old African baobab from Savé Valley, Zimbabwe. Two wood samples were collected from the large inner cavity. Several segments were extracted from these samples and analysed by AMS (accelerator mass spectrometry) radiocarbon dating. We found that the age values of segments increase with the distance into the wood. This major anomaly is characteristic to multi-stemmed baobabs with a closed ring-shaped structure and a false cavity inside. The investigation of the Humani Bedford baobab evinced that the baobab consists of three fused stems. The fourth stem of the ring is missing. The oldest dated segment was found to have a radiocarbon date of 1655 ± 14 BP, which corresponds to a calibrated age of 1575 ± 30 yr. The dating results show that the stems which build the ring stopped growing toward the false cavity more than 600 yr ago. By considering the position of the oldest segment in the investigated stem, we concluded that the Humani Bedford baobab is around 1800 yr old. According to our dating results, the Humani Bedford baobab becomes the oldest living African baobab.
Radiocarbon investigation of a superlative Grandidier Baobab, the Big Reniala of Isosa

(Universitatis Babes-Bolyai, Department of Chemistry, 2019) Patrut, Roxana T. ; Patrut, Adrian ; Pock-Tsy, Jean-Michel Leong ; Woodborne, Stephan ; Rakosy, Laszlo ; Danthu, Pascal ; Ratiu, Ileana-Andreea ; Bodis, Jeno ; von Reden, Karl F.

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.
Final radiocarbon investigation of Platland tree, the biggest African baobab

(Studia Chemia, 2017) Patrut, Adrian ; Woodborne, Stephan ; Patrut, Roxana T. ; Rakosy, Laszlo ; Hall, Grant ; Ratiu, Ileana ; von Reden, Karl F.

The article discloses the main results of our new investigation of Platland tree, a.k.a. Sunland baobab, the largest known African baobab. Our recent research was motivated by the three successive splits of 2016 and 2017, which determined the collapse and demise of the stems that have built the main unit of the tree. According to our new findings concerning the architecture of large and old baobabs, we established that Platland tree has a double closed-ring shaped structure and consists of two units/rings that close two separate false cavities. The larger unit was composed of five fused stems, out of which four toppled and died, while the fifth stem is already broken. The smaller unit, which is still standing, consists of three fused stems. We also determined that the larger unit had an age of 800 yr, while the smaller unit is 1100 yr old.
Software development for continuous-gas-flow AMS

( 2007-09) von Reden, Karl F. ; Roberts, Mark L. ; Jenkins, William J. ; Rosenheim, Brad E. ; McNichol, Ann P. ; Schneider, Robert J.

The National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility at Woods Hole Oceanographic Institution is presently completing installation of a novel continuous-flow AMS system. A multi-year development of an AMS microwave gas ion source in collaboration with Atomic Energy Canada Limited (AECL), Chalk River, has preceded this final step of an implementation that is expected to add a new dimension to 14C AMS. National Instruments, NIM, and CAMAC modules have been programmed with LabVIEW on a Windows XP platform to form the basis for data acquisition. In this paper we discuss possible applications and include simulations of expected data acquisition scenarios like real-time AMS analysis of chromatograms. Particular attention is given to issues of synchronization between rapidly changing input amplitudes and signal processing cycles in hardware and software.
Age, growth and death of a national icon: the historic Chapman baobab of Botswana

(MDPI, 2019-11-05) Patrut, Adrian ; Woodborne, Stephan ; Patrut, Roxana T. ; Hall, Grant ; Rakosy, Laszlo ; Winterbach, Christiaan ; von Reden, Karl F.

The year 2016 witnessed the fall of a symbol of the botanical world: the historic Chapman baobab of Botswana. This article presents the results of our investigation of the standing and fallen tree. The Chapman baobab had an open ring-shaped structure composed of six partially fused stems. Several wood samples collected from the stems prior and after their collapse were analysed by using radiocarbon dating. The radiocarbon date of the oldest sample was 1381 ± 22 BP, which corresponds to a calibrated age of 1345 (+10, −15) calendar years. The dating results show that the six stems of the Chapman baobab belonged to three different generations, which were 1350–1400, 800–1000 and 500–600 years old. The growth rate variation of the largest and oldest stem is presented and correlated with the climate evolution in the area over the past 1000 years. The factors that determined the sudden fall and death of the Chapman baobab are also presented and discussed.
A continuous-flow gas chromatography 14C accelerator mass spectrometry system

(Dept. of Geosciences, University of Arizona, 2010-08) McIntyre, Cameron P. ; Galutschek, Ernst ; Roberts, Mark L. ; von Reden, Karl F. ; McNichol, Ann P. ; Jenkins, William J.

Gas-accepting ion sources for radiocarbon accelerator mass spectrometry (AMS) have permitted the direct analysis of CO2 gas, eliminating the need to graphitize samples. As a result, a variety of analytical instruments can be interfaced to an AMS system, processing time is decreased, and smaller samples can be analyzed (albeit with lower precision). We have coupled a gas chromatograph to a compact 14C AMS system fitted with a microwave ion source for real-time compoundspecific 14C analysis. As an initial test of the system, we have analyzed a sample of fatty acid methyl esters and biodiesel. Peak shape and memory was better then existing systems fitted with a hybrid ion source while precision was comparable. 14C/12C ratios of individual components at natural abundance levels were consistent with those determined by conventional methods. Continuing refinements to the ion source are expected to improve the performance and scope of the instrument.

von Reden Karl F.

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