Research Activities

Main subjects are:

  • Linear high frequency accelerators for protons and ions
  • Ion beam diagnostics
  • Construction of the in house neutron source FRANZ

These topics are sketched in a bit more detail below


Linear high frequency accelerators for protons and ions

The concepts of the KONUS and EQUUS /1,2/ beam dynamics were developed. They allow for new drift tube accelerator designs resulting in compact and efficient ion acceleration.

New welding and production techniques as well as new magnet technologies and RF  drive integration into the cavity will allow for a new boost in linear accelerator layout. The new technologies have to be analysed and transferred into the world of accelerators.

A special topic is the radio frequency quadrupole RFQ development. At present, a first 325 MHz RFQ of the 4-Rod type for proton acceleration is under construction and will be RF power and beam tested during the coming years.

End field investigations result in better matching in and out of the beam /3/.


The working group is offering state of the art simulation tools and is developing and improving own simulation tools where necessary.

Ion beam diagnostics

The ion beam has to be characterized in 6 - dimensional phase space, and for an increasingly wide range of beam current and energy levels. This affords new measurement techniques. Our group began the application of mini-cameras for that purpose /4/. In general destruction free techniques are a main focus of our activities.


Construction of the in house neutron source FRANZ

Small neutron sources for research are of increasing interest as some of the existing research reactors will be shut down in near future. FRANZ is based on a 2 MeV proton beam which will generate neutrons by the (p,n) reaction on a 7Li  target /5/. Main features are the neutron energy spectrum and the 250 kHz /1 ns  pulse specrum which enables diferential neutron capture cross section measurements as needed in nuclear astrophysics or in material research for fusion reactors etc.

At present, beam development from the ion source down to the neutron production target is underway.


Fig.: Beam line from the ion source to the 2 MV RF accelerator.




U. Ratzinger, H. Hähnel, R. Tiede, J. Kaiser, A. Almomani, Combined zero degree structure beam dynamics and applications, Phys. Rev. Accelerators and Beams 22, 114801 (2019)


S. Minaev, U. Ratzinger, H. Podlech, M. Busch, W. Barth, A superconducting, energy variable heavy ion linac with constant β, multi-cell cavities of CH-type, Phys. Rev. ST Accel. Beams 12, 120101 (2009)


M. Schuett, M. Syha, U. Ratzinger, Compensation of longitudinal entrance and exit gap field effects in RFQ's of the 4-Rod type, Nucl. Instr. And Meth. In Phys. Research A 928(2019) p. 58-64


A. Ates, Y. Ates, H. Niebuhr, U. Ratzinger, Non invasive diagnostics of ion beams in toroidal strong magnetic fields with standard CMOS cameras, Nuclear Inst. and Methods in Physics Research A 877 (2017) p. 69-73.


S. Alzubaidi et al., The Frankfurt Neutron Source, Eur. Phys. J. Plus (2016) 131:124