Hans-Arno Synal

Last Name

Synal

First Name

Hans-Arno

ORCID

0000-0001-5621-3089

Show all metadata

Search Results

Publications1 - 10 of 60

BioMICADAS: Compact next generation AMS system for pharmaceutical science
Schulze-König, Tim; Dueker, Stephen R.; Giacomo, Jason; et al. (2010)
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
The next generation Accelerator Mass Spectrometer system specifically designed to address the needs of the growing pharmaceutical science market has passed validation testing. The system dubbed BioMICADAS is based on a previously developed compact carbon dating instrument, the MICADAS. Like its predecessor, it has an overall footprint of only 2.5 × 3 m2 and uses a 200 kV high voltage platform for tandem based ion acceleration. The ion source can accommodate samples as graphite or gaseous CO2. It is equipped with two independently operating vacuum locks, allowing continuous measurement sequence and providing a capacity of ∼20,000 samples per annum. A barcoded cathode tracking system allows data capture into Laboratory Information Management System (LIMS) for Good Laboratory Practices (GLP) regulated work. It can be housed in research laboratories alongside other complementary bioanalytical equipment and operated by general laboratory staff as the system is designed to be robust and user-friendly. The system has undergone rigorous validation over the range from 0.1 to 100 Modern Carbon, including accuracy, linearity, robustness, and precision experiments over the course of 7 months. It has been shipped and installed at the site of our collaborative partner, Vitalea Science in Davis, California. The installation process took ∼2 weeks from boxes to beam. The feasibility of the system to determine the absolute specific activity of biogenic samples was also shown by using the method of isotopic dilution.
A Gas Ion Source for Radiocarbon Measurements at 200 kV
Ruff, Matthias; Wacker, Lukas; Gäggeler, Heinz W.; et al. (2007)
Radiocarbon
The novel tabletop miniaturized radiocarbon dating system (MICADAS) at ETH Zurich features a hybrid Cs sputter negative ion source for the measurement of solid graphite and gaseous CO2 samples. The source produces stable currents of up to 6 μA C− out of gaseous samples with an efficiency of 3–6%. A gas feeding system has been set up that enables constant dosing of CO2 into the Cs sputter ion source and ensures stable measuring conditions. The system is based on a syringe in which CO2 gas is mixed with He and then pressed continuously into the ion source at a constant flow rate. Minimized volumes allow feeding samples of 3–30 μg carbon quantitatively into the ion source. In order to test the performance of the system, several standards and blanks have successfully been measured. The ratios of 14C/12C could be repeated within statistical errors to better than 1.0% and the 13C/12C ratios to better than 0.2%. The blank was <1 pMC.
231Pa/230Th: A proxy for upwelling off the coast of West Africa
Christl, Marcus; Lippold, Jörg; Hofmann, Alexander; et al. (2010)
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
231Pa has widespread applications in the earth sciences including uranium series disequilibrium dating of carbonates and the reconstruction of ocean circulation or bio-productivity on glacial/interglacial timescales. Here we present the first 231Pa profile from a marine sediment core (GeoB3722) located in the large upwelling area off West Africa (Northern Cape Basin) measured with Accelerator Mass Spectrometry (AMS). Together with the Th and U-data (obtained with ICP-MS) 231Pa/230Th ratios were calculated covering the past 30,000 yr. Our results indicate that site GeoB3722 was located in the wind driven upwelling area during glacial times while it abruptly turned into an open ocean area at about 14,000 yr BP. A spatial shift of the large wind driven upwelling area off West Africa is consistent with the idea that atmospheric circulation patterns as well as ocean circulation dramatically changed at the last glacial interglacial transition.
14C Contamination Testing in Natural Abundance Laboratories: A New Preparation Method Using Wet Chemical Oxidation and Some Experiences
McIntyre, Cameron P.; Lechleitner, Franziska; Lang, Susan Q.; et al. (2016)
Radiocarbon
Substances enriched with radiocarbon can easily contaminate samples and laboratories used for natural abundance measurements. We have developed a new method using wet chemical oxidation for swabbing laboratories and equipment to test for 14C contamination. Here, we report the findings of 18 months’ work and more than 800 tests covering studies at multiple locations. Evidence of past and current use of enriched 14C was found at all but one location and a program of testing and communication was used to mitigate its effects. Remediation was attempted with mixed success and depended on the complexity and level of the contamination. We describe four cases from different situations.
Accelerator mass spectrometry of plutonium at 300 kV
Fifield, Leslie K.; Synal, Hans-Arno; Suter, Martin (2004)
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms ~ Proceedings of the Ninth International Conference on Accelerator Mass Spectrometry
Atmospheric transport and deposition of cosmogenic ³⁶Cl using ECHAM6.3-HAM2.3 model
Zheng, Minjie; Muscheler, Raimund; Adolphi, Florian; et al. (2025)
Earth and Planetary Science Letters
The cosmogenic radionuclide ³⁶Cl is a valuable tracer for studying Earth system processes, solar variability and geomagnetic field changes. These applications rely on a comprehensive understanding of ³⁶Cl transport and deposition processes, which are still poorly studied. In this study, we apply a state-of-the-art climate model ECHAM6.3-HAM2.3 to investigate the source distribution and deposition of ³⁶Cl. We configured ³⁶Cl as gas in the stratosphere and as aerosol particles in the troposphere (E63H23CTL). Two sensitivity simulations were performed, with ³⁶Cl configured solely as aerosol particles (E63H23AER) and solely as gas (E63H23GAS). The E63H23CTL simulation agrees well with global ³⁶Cl measurements in terms of absolute values and temporal variability. E63H23AER significantly underestimates polar ³⁶Cl deposition compared to measurements, E63H23CTL and E63H23GAS, suggesting that polar regions are more sensitive to the ³⁶Cl state (aerosol or gas phase) than other regions. This is most likely attributed to the predominance of mixed-phase clouds in the polar regions, which have a higher scavenging efficiency for gaseous ³⁶Cl compared to aerosol-bound ³⁶Cl. This is further supported by comparison with the other cosmogenic radionuclide 10Be, which is exclusively aerosol-bound. The stratospheric contribution is dominant (65–70 %) in ³⁶Cl deposition in polar and subtropical regions, while stratospheric and tropospheric contributions are of similar size (50–51 %) in tropical regions. When responding to changes in solar modulation, ³⁶Cl deposition varies proportionally to global production rate changes. However, as response to geomagnetic field changes, ³⁶Cl shows latitudinal-dependent deposition enhancements/decreases (10–33 %) relative to global production rate changes. This deposition response is insensitive to the forms of ³⁶Cl (gaseous or aerosol-bound) and is similar to that shown by ¹⁰Be. The result indicates that differences in transport and deposition between ¹⁰Be and ³⁶Cl may play a minor role when jointly using these two radionuclides for geomagnetic and solar reconstructions.
Use of Accelerator Mass Spectrometry to Measure the Pharmacokinetics and Peripheral Blood Mononuclear Cell Concentrations of Zidovudine
Vuong, Le T.; Ruckle, Jon L.; Blood, Arlin B.; et al. (2008)
Journal of Pharmaceutical Sciences
The remarkable sensitivity of accelerator mass spectrometry (AMS) is finding many new applications in pharmacology. In this study AMS was used to measure [14C]-Zidovudine (ZDV) concentrations at the drug's site of action (peripheral blood mononuclear cells, PBMCs) following a dose of 520 ng (less than one-millionth of the standard daily dose) to a healthy volunteer. In addition, the pharmacokinetics of this microdose were determined and compared to previously published parameters for therapeutic doses. Microdose ZDV pharmacokinetic parameters fell within reported 95% confidence intervals or standard deviations of most previously published values for therapeutic doses. Blood, urine, stool, saliva, and isolated PBMCs were collected periodically through 96 h postdose and analyzed for ZDV and metabolite concentrations. The results showed that ZDV is rapidly absorbed and eliminated, has one major metabolite, and is sequestered in PBMCs. 14C mass balance assessments indicated a significant portion of ZDV remained after 96 h with a much prolonged elimination half-life. Results of this study demonstrate the usefulness of microdosing and AMS as a tool for studying the pharmacokinetic characteristics, including PBMC concentrations, of ZDV and underscore the value of AMS as a tool with which to perform pharmacokinetic and mass balance studies using trace amounts of radiolabeled compound.
Heliomagnetic and geomagnetic activity cycles on millennial timescales
Beer, Juerg; McCracken, Ken G.; Adolphi, Florian; et al. (2025)
Quaternary Science Reviews
We report 17 new solar activity cycles with periodicities ranging from 1,700 to 18,000 years. Using Bayesian spectral analysis we determined for each cycle period, amplitude and phase for the past 145,000 years. These results were obtained by analyzing 10Be in the 2775 m long EDML ice core from Dronning Maud Land, Antarctica. In addition, we have augmented the 10Be data with synchronous ice accumulation and δ18O data obtained from the same ice core; with paleomagnetic dipole moment data derived mainly from ocean sediments; and with calculated global insolation data. There is a close agreement between the 10Be periodicities in the first and the last 70 kyr intervals. We have developed a new analytical technique we call the “frequency domain differentiation technique” (FDDT) that distinguishes between the periodicities due to (a) variations in the cosmic ray intensity and (b) climate effects related to the accumulation rate. In a first step we have calculated the 10Be flux and then selected all periodicities which are common within 1 % in at least 2 of the investigated parameters (10Be concentration, 10Be flux, accumulation rate, δ18O, and insolation). Using these data we identified a total of 42 statistically significant periodicities. 20 of them are found in the 10Be concentration which we separated into 3 groups of origins: Four due to 10Be production only (group 1: 18012, 6508, 5782, 3833 yr), thirteen being a combination of production and accumulation related (system) effects with the production components being generally larger than the system components (group 2: 15503, 13837, 8441, 7722, 7136, 4695, 4556, 4110, 3961, 3292, 3104, 2025, 1680 y), and three being related to system effects only (group 3: 23971, 21101, 11637 y). In a second step we used independent paleomagnetic information to distinguish between heliomagnetic and geomagnetic periodicities in the 10Be production. We find an overall good agreement between the 10Be flux and the dipole moment in the time domain. In the frequency domain there is evidence for system effects in the geomagnetic data. Due to inconsistencies between the paleomagnetic records we do not draw conclusions regarding a potential geomagnetic origin of the 10Be cycles found in the EDML ice core.
Rapid, continuous radiocarbon analysis of carbonate archives using laser ablation
Wertnik, Melina; Welte, Caroline; Wacker, Lukas; et al. (2020)
EGUsphere
Accelerator Mass Spectrometry: Ultra-sensitive Detection Technique of Long-lived Radionuclides
Synal, Hans-Arno (2022)
Chimia
An introduction is given to accelerator mass spectrometry (AMS) technology, to the fundamental measurement principles, and the physics aspects behind the design constraints of AMS instruments. This article shall give an overview on technical design constrains of AMS instrumentation, general ion optical principles, and nuclide specific problems. The historic development of AMS detection techniques is briefly summarized. The wide variety of applications connected to the AMS technology are not discussed.

Publications1 - 10 of 60

Hans-Arno Synal

Last Name

First Name

ORCID

Organisational unit

Filters

Search Results