Chemical Elements as Tracers of the Evolution of the Cosmos


Ion Accelerator Facility, Physikalisch-Technische Bundesanstalt (Braunschweig, Germany)


The Physikalisch-Technische Bundesanstalt (PTB) is the German national institute for science and technology and the highest technical authority for metrology and certain sectors of safety engineering. It operates under the auspices of the Federal Minister of Economics and has 2000 employees. Within division 6 ‘Ionizing Radiation’, the department 6.4 ‘Neutron Radiation’ operates two particle accelerators for producing charged particle, neutron and high-energy photon fields.

The PTB ion accelerator facility (PIAF) consists of two low-energy ion accelerators and ancillary equipment. The TCC CV-28 variable-energy isochronous cyclotron provides beams of protons (E < 19 MeV, I < 80 μA), deuterons (E < 13.5 MeV, I < 80 μA) and alpha particles (E < 28 MeV, I < 20 μA). Complementary, the same ion beams are available with energies up to 4 MeV (protons, deuterons) or 6 MeV (alpha particles) in the low energy region and with similar currents from a HVEE Tandetron accelerator. Experiments with almost mono-energetic neutrons in the energy range from 20 keV to 20 MeV are performed in the centre of a very large experimental hall in open geometry. All ion beams are available in DC or ns-pulsed mode for experiments with adjustable repetition rate for time-of-flight (TOF). Experiments using neutron beams with continuous (‘white’) energy distribution can be performed at the multi-detector TOF spectrometer connected to the main beam line of the cyclotron. Neutron energies are selected using the TOF method with flight paths between 12 m and 30 m.

Services currently offered

One of the main tasks at PIAF is the production of neutron reference fields (ISO) for the characterization and calibration of neutron detectors and dosemeters relative to primary reference instruments for neutron fluence measurements. Cross sections for nuclear reactions induced by neutrons and charged particles can be measured using the various ion beams and the monoenergetic and ‘white’ neutron beams and fields.

For external users, PIAF is operated in a two-shift (16 h) mode from Monday to Thursday. On special request, also three-shift (24 h) operation is possible. Support by the technical staff of PIAF, access to the mechanical and electronics workshops and a guesthouse are available for external users. Instructions on radiation safety and safety at workplaces are given prior to each beam time. Beam time is distributed per three-month intervals. There is no external program advisory committee. Scheduling of beam time is organized on regular meetings of senior staff members. Priority is given to requests for calibration services according to the statuary tasks of PTB, to projects related to externally funded access schemes and to projects with involvement of external or internal PhD students. External users are requested to contribute to the operational cost of the facility according to the ‘Cost Regulations for Services Rendered by the PTB’ or via transnational access schemes or bilateral contracts with PTB.

Linked ChETEC institution

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ChETEC contact person

  • Ralf Nolte (