Search

Your search keyword '"Golser, Robin"' showing total 311 results
Start Over Author "Golser, Robin"
311 results on '"Golser, Robin"'

1. Detection of $^{135}$Cs & $^{137}$Cs in environmental samples by AMS

Author

Wieser, Alexander, Lachner, Johannes, Martschini, Martin, Zok, Dorian, Priller, Alfred, Steier, Peter, and Golser, Robin

Subjects
Physics - Instrumentation and Detectors
Abstract

The detection of low abundances of $^{135}$Cs in environmental samples is of significant interest in different fields of environmental sciences, especially in combination with its shorter-lived sister isotope $^{137}$Cs. The method of Ion-Laser InterAction Mass Spectrometry (ILIAMS) for barium separation at the Vienna Environmental Research Accelerator (VERA) was investigated and further improved for low abundance cesium detection. The difluorides BaF$_2^-$ and CsF$_2^-$ differ in their electron detachment energies and make isobar suppression with ILIAMS by more than 7 orders of magnitude possible. By this method, samples with ratios down to the order of $^{135,137}$Cs/$^{133}$Cs $\approx 10^{-11}$ are measurable and the $^{135}$Cs/$^{137}$Cs ratios of first environmental samples were determined by AMS., Comment: We acknowledge funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 101008324 (ChETEC-INFRA)

Published
2024
Full Text
View/download PDF

7. Precise measurement of the thermal and stellar $^{54}$Fe($n, \gamma$)$^{55}$Fe cross sections via AMS

Author

Wallner, Anton, Belgya, Tamas, Buczak, Kathrin, Coquard, Laurent, Bichler, Max, Dillmann, Iris, Golser, Robin, Käppeler, Franz, Karakas, Amanda, Kutschera, Walter, Lederer, Claudia, Mengoni, Alberto, Pignatari, Marco, Priller, Alfred, Reifarth, Rene, Steier, Peter, and Szentmiklosi, Laszlo

Subjects
Nuclear Experiment, Astrophysics - Solar and Stellar Astrophysics
Abstract

The detection of long-lived radionuclides through ultra-sensitive single atom counting via accelerator mass spectrometry (AMS) offers opportunities for precise measurements of neutron capture cross sections, e.g. for nuclear astrophysics. The technique represents a truly complementary approach, completely independent of previous experimental methods. The potential of this technique is highlighted at the example of the $^{54}$Fe($n, \gamma$)$^{55}$Fe reaction. Following a series of irradiations with neutrons from cold and thermal to keV energies, the produced long-lived $^{55}$Fe nuclei ($t_{1/2}=2.744(9)$ yr) were analyzed at the Vienna Environmental Research Accelerator (VERA). A reproducibility of about 1% could be achieved for the detection of $^{55}$Fe, yielding cross section uncertainties of less than 3%. Thus, the new data can serve as anchor points to time-of-flight experiments. We report significantly improved neutron capture cross sections at thermal energy ($\sigma_{th}=2.30\pm0.07$ b) as well as for a quasi-Maxwellian spectrum of $kT=25$ keV ($\sigma=30.3\pm1.2$ mb) and for $E_n=481\pm53$ keV ($\sigma= 6.01\pm0.23$ mb). The new experimental cross sections have been used to deduce improved Maxwellian average cross sections in the temperature regime of the common $s$-process scenarios. The astrophysical impact is discussed using stellar models for low-mass AGB stars.

Published
2016
Full Text
View/download PDF

8. The Link Between the Local Bubble and Radioisotopic Signatures on Earth

Author

Feige, Jenny, Breitschwerdt, Dieter, Wallner, Anton, Schulreich, Michael M., Kinoshita, Norikazu, Paul, Michael, Dettbarn, Christian, Fifield, L. Keith, Golser, Robin, Honda, Maki, Linnemann, Ulf, Matsuzaki, Hiroyuki, Merchel, Silke, Rugel, Georg, Steier, Peter, Tims, Stephen G., Winkler, Stephan R., and Yamagata, Takeyasu

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

Traces of 2-3 Myr old 60Fe were recently discovered in a manganese crust and in lunar samples. We have found that this signal is extended in time and is present in globally distributed deep-sea archives. A second 6.5-8.7 Myr old signature was revealed in a manganese crust. The existence of the Local Bubble hints to a recent nearby supernova-activity starting 13 Myr ago. With analytical and numerical models generating the Local Bubble, we explain the younger 60Fe-signature and thus link the evolution of the solar neighborhood to terrestrial anomalies., Comment: 4 pages, 3 figures, accepted for publication in JPS Conf. Proc

Published
2016
Full Text
View/download PDF

15. Spontaneous and photo-induced decay processes of WF5− and HfF5− molecular anions in a cryogenic storage ring.

Author

Gnaser, Hubert, Martschini, Martin, Leimbach, David, Karls, Julia, Hanstorp, Dag, Indrajith, Suvasthika, Ji, Mingchao, Martini, Paul, Simonsson, Ansgar, Zettergren, Henning, Schmidt, Henning T., and Golser, Robin

Subjects
ACCELERATOR mass spectrometry, STORAGE rings, ANIONS, THRESHOLD energy, LASER ranging, NUCLEOSYNTHESIS
Abstract

Spontaneous and photo-induced decay processes of HfF5− and WF5− molecular anions were investigated in the Double ElectroStatic Ion Ring ExpEriment (DESIREE). The observation of these reactions over long time scales (several tens of ms) was possible due to the cryogenic temperatures (13 K) and the extremely low residual gas pressure (∼10−14 mbar) of DESIREE. For photo-induced reactions, laser wavelengths in the range 240 to 450 nm were employed. Both anion species were found to undergo spontaneous decay via electron detachment or fragmentation. After some ms, radiative cooling processes were observed to lower the probability for further decay through these processes. Photo-induced reactions indicate the existence of an energy threshold for WF5− anions at about 3.5 eV, above which the neutralization yield increases strongly. By contrast, HfF5− ions exhibit essentially no enhanced production of neutrals upon photon interaction, even for the highest photon energy used in this experiment (∼5.2 eV). This suppression will be highly beneficial for the efficient detection, in accelerator mass spectrometry, of the extremely rare isotope 182Hf using the 182HfF5− anion while effectively reducing the interfering stable isobar 182W in the analyte ion 182WF5−. The radionuclide 182Hf is of great relevance in astrophysical environments as it constitutes a potential candidate to study the events of nucleosynthesis that may have taken place in the vicinity of the solar system several million years ago. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

19. Detection of 135Cs & 137Cs in environmental samples by AMS

Author

Wieser, Alexander, Lachner, Johannes, Martschini, Martin, Zok, Dorian, Priller, Alfred, Steier, Peter, Golser, Robin, Wieser, Alexander, Lachner, Johannes, Martschini, Martin, Zok, Dorian, Priller, Alfred, Steier, Peter, and Golser, Robin

Abstract

The detection of low abundances of 135Cs in environmental samples is of significant interest in different fields of environmental sciences, especially in combination with its shorter-lived sister isotope 137Cs. The method of Ion–Laser InterAction Mass Spectrometry (ILIAMS) for barium separation at the Vienna Environmental Research Accelerator (VERA) was investigated and further improved for low abundance cesium detection. The difluorides BaF2- and CsF2- differ in their electron detachment energies and make isobar suppression with ILIAMS by more than 7 orders of magnitude possible. By this method, samples with ratios down to the order of 135,137Cs/133Cs ˜10-11 are measurable and the 135Cs/137Cs ratios of first environmental samples were determined by AMS.

Published
2023

30. The quest for AMS of 182Hf – why poor gas gives pure beams

Author

Martschini Martin, Lachner Johannes, Merchel Silke, Priller Alfred, Steier Peter, Wallner Anton, Wieser Alexander, and Golser Robin

Subjects
Physics, QC1-999
Abstract

The long-lived radioisotope 182Hf (T1/2 = 8.9 Ma) is of high astrophysical interest as its potential abundance in environmental archives would provide insight into recent r-process nucleosynthesis in the vicinity of our solar system. Despite substantial efforts, it could not be measured at natural abundances with conventional AMS so far due to strong isobaric interference from stable 182W. Equally important is an increase in ion source efficiency for the anions of interest. The new Ion Laser InterAction Mass Spectrometry (ILIAMS) technique at VERA tackles the problem of elemental selectivity in AMS with a novel approach. It achieves near-complete suppression of isobar contaminants via selective laser photodetachment of decelerated anion beams in a gas-filled radio-frequency quadrupole (RFQ) ion cooler. The technique exploits differences in electron affinities (EA) within elemental or molecular isobaric systems neutralizing anions with EAs smaller than the photon energy. Alternatively, these differences in EA can also facilitate anion separation via chemical reactions with the buffer gas. We present first results with this approach on AMS-detection of 182Hf. With He +O2 mixtures as buffer gas in the RFQ, suppression of 182WF5− vs 180HfF 5− by >105 has been demonstrated. Mass analysis of the ejected anion beam identified the formation of oxyfluorides as an important reaction channel. The overall Hf-detection efficiency at VERA presently is 1.4% and the W-corrected blank value is 182Hf/180Hf = (3.4 ± 2.1)×10−14. In addition, a survey of different sample materials for highest negative ion yields of HfF 5− with Cs-sputtering has been conducted.

Published
2020
Full Text
View/download PDF

32. AMS of 36Cl with the VERA 3 MV tandem accelerator

Author

Martschini, Martin, Andersson, Pontus, Forstner, Oliver, Golser, Robin, Hanstorp, Dag, Lindahl, Anton O., Kutschera, Walter, Pavetich, Stefan, Priller, Alfred, Rohlén, Johan, Steier, Peter, Suter, Martin, and Wallner, Anton

Published
2013
Full Text
View/download PDF

34. Anthropogenic U-236 and U-233 in the Baltic Sea : Distributions, source terms, and budgets

Author

Lin, Mu, Qiao, Jixin, Hou, Xiaolin, Steier, Peter, Golser, Robin, Schmidt, Martin, Dellwig, Olaf, Hansson, Martin, Bäck, Örjan, Vartti, Vesa-Pekka, Stedmon, Colin, She, Jun, Murawski, Jens, Aldahan, Ala, Schmied, Stefanie A. K., Lin, Mu, Qiao, Jixin, Hou, Xiaolin, Steier, Peter, Golser, Robin, Schmidt, Martin, Dellwig, Olaf, Hansson, Martin, Bäck, Örjan, Vartti, Vesa-Pekka, Stedmon, Colin, She, Jun, Murawski, Jens, Aldahan, Ala, and Schmied, Stefanie A. K.

Published
2022
Full Text
View/download PDF

36. Developing Accelerator Mass Spectrometry Capabilities for Anthropogenic Radionuclide Analysis to Extend the Set of Oceanographic Tracers

Author

Hain, Karin, primary, Martschini, Martin, additional, Gülce, Fadime, additional, Honda, Maki, additional, Lachner, Johannes, additional, Kern, Michael, additional, Pitters, Johanna, additional, Quinto, Francesca, additional, Sakaguchi, Aya, additional, Steier, Peter, additional, Wiederin, Andreas, additional, Wieser, Alexander, additional, Yokoyama, Akihiko, additional, and Golser, Robin, additional

Published
2022
Full Text
View/download PDF

45. Natural and anthropogenic 236U in environmental samples

Author

Steier, Peter, Bichler, Max, Keith Fifield, L., Golser, Robin, Kutschera, Walter, Priller, Alfred, Quinto, Francesca, Richter, Stephan, Srncik, Michaela, Terrasi, Philippo, Wacker, Lukas, Wallner, Anton, Wallner, Gabriele, Wilcken, Klaus M., and Maria Wild, Eva

Published
2008
Full Text
View/download PDF

47. 70-Year Anthropogenic Uranium Imprints of Nuclear Activities in Baltic Sea Sediments

Author

Lin, Mu, Qiao, Jixin, Hou, Xiaolin, Dellwig, Olaf, Steier, Peter, Hain, Karin, Golser, Robin, Zhu, Liuchao, Lin, Mu, Qiao, Jixin, Hou, Xiaolin, Dellwig, Olaf, Steier, Peter, Hain, Karin, Golser, Robin, and Zhu, Liuchao

Abstract

A strongly stratified water structure and a densely populated catchment make the Baltic Sea one of the most polluted seas. Understanding its circulation pattern and time scale is essential to predict the dynamics of hypoxia, eutrophication, and pollutants. Anthropogenic 236U and 233U have been demonstrated as excellent transient tracers in oceanic studies, but unclear input history and inadequate long-term monitoring records limit their application in the Baltic Sea. From two dated Baltic sediment cores, we obtained high-resolution records of anthropogenic uranium imprints originating from three major human nuclear activities throughout the Atomic Era. Using the novel 233U/236U signature, we distinguished and quantified 236U inputs from global fallout (45.4-52.1%), Chernobyl accident (0.3-1.8%), and discharges from civil nuclear industries (46.1-54.3%) to the Baltic Sea. We estimated the total release of 233U (7-15 kg) from the atmospheric nuclear weapon testing and pinpointed the 233U peak signal in the mid-to-late 1950s as a potential time marker for the onset of the Anthropocene Epoch. This work also provides fundamental 236U data on Chernobyl accident and early discharges from civil nuclear facilities, prompting worldwide 233U-236U tracer studies. We anticipate our data to be used in a broader application in model-observation interdisciplinary research on water circulation and pollutant dynamics in the Baltic Sea.

Published
2021

48. On the Quality Control for the Determination of Ultratrace-Level 236U and 233U in Environmental Samples by Accelerator Mass Spectrometry

Author

Lin, Mu, Qiao, Jixin, Hou, Xiaolin, Golser, Robin, Hain, Karin, Steier, Peter, Lin, Mu, Qiao, Jixin, Hou, Xiaolin, Golser, Robin, Hain, Karin, and Steier, Peter

Abstract

Our recent attempt to determine ultratrace-level 236U and 233U in small-volume seawater samples was challenged by high and unstable procedure blanks in our environmental radioactivity laboratory, which used to be a spent fuel research facility. Through intercomparison experiments with different laboratories and background checks on the chemical reagents and laboratory dust, the resuspended U-bearing dust was identified as the dominating source of the 236U and 233U contamination. With the implementation of background control (especially dust control) measures, the procedure blanks and detection limits of 236U and 233U for the radiochemical separation procedure have been significantly improved by three orders of magnitudes. With well-controlled blanks, the analytical precision for 236U and 233U predominantly relies on the AMS counting statistics. Background check and dust control are strongly recommended before the analyses of environmental-level long-lived radionuclides (such as 236U and 233U) that are conducted in the former or active nuclear facilities, even if clearance of radioactivity relevant for radioprotection was achieved.

Published
2021

Catalog

Books, media, physical & digital resources
See catalog results