Prof. Dr. Anton Wallner

Head Accelerator Mass Spectrometry and Isotope Research
Phone: +49 351 260 3274


Currently, all our AMS measurements are performed in the 6 MV AMS facility at HZDR, DREAMS. The 6 MV tandetron at HZDR is also coupled to a SIMS system, which allows us to perform Super-SIMS measurements of trace elements in different materials. While some of the samples are chemically prepared and loaded into AMS targets by our users before sending them to us, our group also has two fully equipped chemistry laboratories. These labs are available for some users who prefer to process the samples at HZDR, and are used by our team for those samples related to our own research projects.

A new AMS facility, HAMSTER, will be installed at HZDR in 2023/2024. While DREAMS is considered a large AMS facility, HAMSTER will be a compact AMS facility, operating with a 1 MV pelletron. This facility will also include the new system for laser-based isobar suppression, ILTIS, whose performance will be previously evaluated in our new test station (or Teststand, in German). The new facility also hosts two new chemistry labs for anthropogenic and ultra-low concentration nuclides, respectively.

DREAMS (6 MV AMS system)

The AMS facility DREAMS (DREsden Accelerator Mass Spectrometry facility) has been installed in 2011. The system is based on a 6 MV tandetron manufactured by High Voltage Engineering Europa (HVE). This accelerator also includes several other beamlines used independently by other groups within the Institute of Ion Beam Physics and Materials Research at HZDR.

The DREAMS facility includes two different ion sources. One of them is a modified version of the HVE ion source SO-110A, developed by the group and specifically designed to reduce cross-contamination between samples. This ion source is mainly used for radiohalide AMS (36Cl and 129I).

For 10Be and 36Cl measurements, the degrader method is used, where a silicon nitride foil is inserted between the analyzing magnet and the 35° electrostatic analyzer, thereby providing effective suppression of 10B and 36S, respectively.

The DREAMS facility is currently used for routine AMS measurements of 7Be, 10Be, 26Al, 36Cl, 41Ca, 55Fe and 129I.

DREAMS 6 MV AMS system ©René Ziegenrücker

Basic scheme of the 6 MV AMS system at HZDR, DREAMS

SIMS and Super-SIMS (SuSI)
Cameca IMS 7fauto SIMS ©HZDR/Tina Pereira

Top view of the Cameca IMS 7fauto SIMS tool

The group also hosts a secondary-ion mass spectrometer (Cameca IMS 7fauto). Besides the possibility of performing conventional SIMS measurements, the system is coupled to the 6 MV tandetron accelerator through the 0° port of the bouncer magnet (see basic scheme of the 6-MV AMS system), allowing so-called Super‑SIMS measurements by sending a beam to the high-energy side of DREAMS. Thanks to such a combination, measurements of stable elements at the ultra-trace level are possible. Detection limits are typically 2-3 orders of magnitude lower compared to conventional SIMS.

Work is performed also in close coordination with the Helmholtz Institute Freiberg for Resource Technology. The method requires well polished and flat solid samples with a maximum diameter of 1 inch (25.4 mm). Standard/reference materials are used in order to calibrate our measurements.

Teststand ©Dr. Carlos Vivo-Vilches

Photo of the Teststand on 16.02.2022

As part of the studies for laser-based isobar suppression of the AMS group in Dresden, a test station is being installed. The test station consists of:

  • A HVE SO-110 Cs sputtering ion source. This source has the same design as the original ion source installed at DREAMS.
  • An upgraded version of the octogonal XY-steerer used in the VERA facility at the University of Vienna, designed and manufactured at HZDR. The new version adds focusing capabilities similar to those of an Einzel lens. Consequently, it is called an Einzelsteerer.
  • A magnetic dipole, which provides the mass selection of the ions.
  • The new version of the laser-based isobar suppressor, ILTIS (Ion Linear Trap for Isobar Suppression), which is being designed at HZDR in collaboration with the group of Isotope Physics of the University of Vienna.

This system is used to test the performance of ILTIS, which will become part of the new compact AMS system. Furthermore, we test the capabilities of other elements for ion beam transport.

Chemistry labs

AMS measurements of long-lived radionuclides are usually only possible if samples are chemically treated, since the original samples (water, rocks etc.) that contain reasonable amounts of radionuclides are too big (100 g - 10 kg). In other words, the radionuclide concentrations in the range of sub-ppq are too low to allow an analysis of typical 1 mg targets. Besides, the chemical separation is doing most of the work reducing the troublesome isobars, and eliminating possible contamination from other sources. For instance, the analysis of cosmogenic 10Be in quartz can only be performed correctly if samples were first cleaned from atmospherically produced 10Be. The preparation of 10Be, 26Al, and 41Ca AMS targets needs the use of large quantities of hydrochloric acid (HCl). Therefore, these should preferably be performed in a separated place than 36Cl and 129I AMS target preparation, keeping the risk of cross-contamination as low as possible. At DREAMS, we have a dedicated lab for 36Cl and 129I sample preparation since autumn 2009.

HAMSTER (1 MV AMS system, coming soon)

In 2023, the AMS group at HZDR will start to install the new compact dedicated AMS facility, HAMSTER (Helmholtz Accelerator Mass Spectrometer Tracing Environmental Radionuclides). This system will be based on a pelletron tandem accelerator with a maximum terminal voltage of 1 MV. The main features of this new system will be:

  • Two different low energy injection lines. One of those will include a laser-based isobar suppressor, ILTIS (Ion Linear Trap for Isobar Suppression).
  • Capability to measure AMS radionuclides for a wide range of masses (7≤A≤320).
  • An ultra-sensitive high energy spectrometer, including a second analyzing magnet.
  • SIMS will be moved to the HAMSTER facility, so more flexible Super-SIMS measurements can be performed there.

The new building hosting HAMSTER (building 705 at HZDR, finished 06/2023) will also house two new chemical laboratories. One will be dedicated to processing of samples with low concentrations of radionuclides (e.g. cosmogenic production), while the second will also allow processing of samples with higher concentrations (e.g. anthropogenic radionuclides).

HAMSTER 1MV AMS system ©National Electrostatic Corp.

Schematic view of the new 1-MV AMS system at HZDR, HAMSTER (©National Electrostatic Corp.)