The Vienna Environmental Research Accelerator (VERA) is a large-scale research facility dedicated to Accelerator Mass Spectrometry (AMS). The primary objective of our research activities is the advancement of the AMS method and associated instrumentation through the application of fundamental physical principles. This allows AMS to be employed in research areas where it was previously not feasible to do so.

Based at the Faculty of Physics of the University of Vienna, the laboratory is managed and operated by a mix of permanent staff and technicians, as well as the next generation of scientists, such as BSc, MSc, PhD students and postdocs. Like many other large-scale facilities, most of us at VERA come from physics or chemistry backgrounds, but we also have experience in interdisciplinary research and geoscience applications. As well as conducting research and analyses, we also participate in outreach activities and often hold tours for the public and local schools.

Scientists use accelerator mass spectrometry (AMS) to measure long-lived radionuclides produced by anthropogenic activities or cosmic radiation. By analysing their concentrations, the Earth’s history from a few tens of years up to millions of years ago can be unravelled. Typical samples from a geochemical context that can be analysed by AMS are:

• water, snow, and ice
• soil samples
• sediments from rivers, lakes, alluvial fans, or (deep-sea) marine environments
• bedrock and boulders affected by glaciers and tectonics
• peat, corals, meteorites…

Dating of sudden mass movements from volcanic eruptions, rock avalanches, tsunamis, meteorite impacts, and earthquakes is possible; and slower processes such as glacial movements, river incisions, erosion and denudation processes can also be quantified.

AMS measurements on most sample types require preparation by chemical treatment in order to deplete the matrix, enrich the radionuclide of interest, reduce interfering isobars and eliminate possible contamination from other sources. For example, analysis of cosmogenic in-situ produced ¹⁰Be in quartz can only be performed if the samples have first been cleaned of atmospheric ¹⁰Be. In certain cases, you can even perform AMS without any chemical preparation, for example at VERA we have a new Ion-Laser Interaction Mass Spectrometry (ILIAMS) system for isobar suppression.  The detection limits can be as low as 10^-15 for radionuclide atoms/stable nuclide atoms, e.g. ¹⁰Be/⁹Be.

Compared to the usually time-consuming preceding chemical preparation of samples (a few days to weeks), the actual AMS analysis is quite fast. We set up our AMS system for best performance within a few hours using blanks and standards. Unknown samples are placed in the same sample wheel (up to 40 positions) and are measured in batches together with standards for normalisation and processing blanks. In order to monitor and control the stability of the measurement conditions, each sample, blank and standard is repeatedly measured in several turns. We usually combine several projects into one measurement campaign, and after a few days, all data from all projects is collected.