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Research

Research projects focus on the exploration of our world by means of the "isotope language", utilizing both natural and anthropogenic long-lived radioisotopes. We pursue fundamental physics experiments and a large variety of interdisciplinary research programs. Research at VERA contributes to the faculty research area "Physics and the Environment". Further contributions to this research area are projects dealing with radioactivity from natural sources. Nuclear reaction studies are performed in international collaboration at research centers like CERN in Geneva, Switzerland or the Institute for Reference Materials and Measurements of the European Commission in Geel, Belgium.

Accelerator Mass Spectroscopy (AMS)

VERA Accelerator
VERA Accelerator

A good balance between technical developments and challenging applications is vital. The applications touch almost every issue of our environment at large, from archaeology to climate research. Special emphasis is put on AMS applications within physics, i.e. Astrophysics, Nuclear Physics, and Atomic and Molecular Physics. One focus of our technical developments is pushing the limits of the AMS method, e.g. of accuracy, reliability, and sample size for the most important AMS isotope 14C. Further emphasis is on the detection of the heaviest radioisotopes (236U, 244Pu). We strive to establish conditions which enable AMS of radioisotopes over the whole nuclear chart.

14C Dating

The probably best-known and most important application of AMS is 14C dating. Thus in the research program of the VERA laboratory the 14C method also plays a main part. Several formal and informal research projects with partners from different research disciplines are currently performed. Worth to mention is the special research program SCIEM2000 (“The Synchronisation of Civilisations in the Eastern Mediterranean in the Second Millennium BC”) funded by the Austrian Science Fund (FWF) and the Austrian Academy of Sciences, which had been completed in 2011.

A method developed to deal with μg carbon samples for 14C dating of DNA (14C produced during nuclear weapon tests in the 1950s and early 1960s) samples is also to be extended to earth and environmental sciences questions.

10Be and 26Al AMS applications

The investigation of possible refinements and improvements in the overall detection efficiency of 26Al from ice samples is pursued. The aim is the refinement of the presently used method for the determination of the 26Al/10Be ratio as a cosmogenic “clock” for dating of old (0.5 to 5 million years) ice from drill-cores from Antarctica.

A new application of 10Be determinations has been started for the assessment of the impact cratering process of the Bosumtwi crater in Ghana.

Investigation of anthropogenic 236U and Pu

VERA defines the state of the art for measuring natural and anthropogenic actinides such as 236U, and 239-244Pu. Measurements of water and sediments from the Irish Sea (affected by the Sellafield nuclear waste reprocessing plant) as well as samples taken remote from possible local contributions to investigate the global fallout from nuclear weapon tests and accidental releases have been performed.

Emphasis is put on establishing 236U as an oceanographic tracer. 236U is one of the most abundant anthropogenic radioisotopes, but only recent advances in AMS allow for the required detection sensitivity. The environmental distribution is largely unexplored and measurements at VERA are usually a first in the field.

Further development of the AMS method

Extending the AMS method to isotopes previously difficult or impossible to measure is an important research activity at VERA. Laser photo detachment of molecular anions which are crucial for a number of interesting AMS isotopes, e.g. 182Hf, is explored.

Neutron induced nuclear reactions

Cross section measurements at the n_TOF facility at CERN

n_TOF experimental area
n_TOF experimental area

We participate in the n_TOF (neutron time-of-flight) collaboration at the European Laboratory for Particle Physics (CERN) . Neutron capture cross sections relevant to the understanding of element synthesis in stars and supernovae as well as neutron capture and fission cross sections on actinides, which are of interest to possible advanced nuclear fuel cycles, are measured at CERN’s n_TOF facility. The n_TOF facility, located in an underground tunnel at the CERN site, consists of a pulsed spallation neutron source, a 185-m flight tube and an experimental area with various detectors for reaction studies and beam monitoring. Spallation neutrons are produced in a lead target by 20-GeV protons from the CERN proton synchrotron. The proton pulse width of about 6 ns and the long flight path result in an excellent neutron energy resolution employing the time-of-flight technique.

 

Environmental Radiation

European Geogenic Radon Map (EGRM)

We participate in an international collaboration to create a European Geogenic Radon Map (EGRM) coordinated by the European Commission – Joint Research Centre, Institute for Transuranium Elements. Within this international effort, indoor measurements, soil-gas measurements and radionuclide analysis in the soil were performed in Upper Austria in collaboration with Austrian universities and government agencies. The measurement results are used to correlate the different measured quantities with the radon potential of the areas and vice versa to predict a radon potential for an area from very different measured quantities (e.g. concentration of radionuclides in the ground, dose-rates, geological information etc.).

Radon Potential in Austria

In a new project (funded by the Federal Ministry of Agriculture, Forestry, Environment and Water Management) the question is raised if already existing radon data from schools, kindergartens and official buildings can be integrated into the Austrian Radon Potential Map.
  
More information on indoor Radon concentration in Austria can be found on the National Survey of Indoor Radon Concentration Homepage.

Stable Isotope Mass Spectrometry

Paleodiet studies via δ13C and δ15N determinations in bone collagen are conducted by elemental analyzer - isotope ratio mass spectrometry, a “conventional” (not accelerator based) mass spectrometry technique.

Nuclear Reactions with Light Heavy-Ions

Measurements of light ion induced nuclear reactions

Excitation functions for the formation of different reaction products with light heavy-ions (6,7Li, 9Be) near the Coulomb barrier are measures at the VERA accelerator of the Faculty of Physics. Stable reaction products are identified by prompt gamma-ray emission during the de-excitation of the compound nuclei, radioactive ones by their decay gamma-radiation.

Nuclear model calculations

Model calculations of nuclear reactions with light heavy-ions are mainly performed using the EMPIRE-II nuclear model code package. The calculations are now extended also to heavier isotopes. Besides the EMPIRE-II model code other types of calculations were tested to compute complete fusion cross sections close to and below the Coulomb barrier. Cross sections in this energy regime are important in nuclear astrophysics and for experiments trying to produce super-heavy elements. As they are very small measurements are either very difficult or are even impossible to perform.

University of Vienna
Isotope Research and Nuclear Physics

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1090 Wien

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