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At the Institute for Nuclear Physics two Tandem accelerators are installed, the 6 MV Tandetron which is dedicated for accelerator mass spectrometry (AMS) as well as an 10 MV FN-Tandem accelerator, which is used for AMS, nuclear structure experiments and also experiments relevant for nuclear astrophysics.

6 MV Cologne AMS Tandem accelerator:

This accelerator can measure very small isotope ratios of down to (bis 10-16).

10 MV FN Tandem accelerator:

The FN accelerator has a maximum voltage of 10 MV and is charged via a Pelletron. Two different sources are available to produce negative ion beams: 3He and 4He beams are deliverd by a Duo-Plasmatron and all other kinds of ion beams are produced by a sputter source. Typical beam intensities can range between a few nA up to about 800 nA for protons and heavy ion beams. Helium beams can reach intensities of up to 200 nA. For questions regarding a specific ion beam, please contact Dr. Christoph Fransen (

Experiments at the FN accelerator:

Different experimental setups are available at the 10 MV Tandem accelerator:

Horus spectrometer

HORUS is a γ-ray spectrometer equipped with 14 HPGe detectors which are mounted under five different angles with respect to the beam axis. Six detectors are equipped with BGO shields for an active Compton suppression. It is possible to mount LaBr-scintillators within the spectrometer. Different target chambers can be installed in HORUS which can be used for very different experimental goals.

The target chamber dedicated for nuclear astrophysics features a very compact design and allows to move all detectors very close to the chamber for maximum efficiency. In addition, the chamber is electrically isolated which allows to measure the beam intensity very precisely. A detailed description of the target chamber used for nuclear astrophysics can be found in F. Heim et al., Nucl. Instr. Meth. Phys. Res. A 966 (2020) 163854 (arxiv:

The SONIC target chamber allows to mount additional silicon detectors for charged particle detection. Hence, particle-gamma coincidence events can be observed and used to create Excitation-Gamma-ray matrices. For further information, see the corresponding publication (arxiv:





Transnational access for beam time within the ChETEC-INFRA project

ChETEC-INFRA provides transnational access to in total 13 infrastuctures networked in the project. This possibility allows scientific users to get beam time free of charge at a facility outside of their own country. Scientists outside of Germany can apply for transnational access at the University of Cologne. See this info-pdf for detailed description and how you can apply.