Development of a new UCN physics lab at the FRM-2

For the new UCN source at the FRM-2 reactor to be operational in 2013, we are working on the development of a beam line with several beam positions for fundamental physics applications:

The largest effort of our group is an experiment position optimized for a measurement of the EDM of the neutron. Next to magnetic stabilization and control of experimental parameters, the laboratory can be adjusted in height. Furthermore, we are planning to install a neutron phase space transformer facility, potentially for the realization of a cold neutron beam with extreme brightness. The expected densities in the experiments take into account production in the deuterium UCN source, losses along the guides and the volumes of guides and experiments. As a function of filling time, a density equilibrium of UCN in the EDM experiment of > 6000 per cc is expected. For details on the successful tests of neutron guide sections and detailed estimates of the source performance contact Andreas Frei (

Along the beam-line we are planning a superconducting magnet to polarize UCN. However, to provide a unique handly on systematic effects in the EDM experiment, the magnet is combined with a resonant RF spin flipper. This can be used to provide an energy-adjustable polarized UCN spectrum based on Zeeman splitting.

Polarized beam