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.

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.

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.

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.

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).