In order to achieve high resolution in a neutron experiment, most of the neutrons in the broad spectrum provided by the neutron source are wasted during monochromatisation or selection of narrow wavelength bands. Theoretically it would be possible to directly produce wavelength-packets of much enhanced intensity even at a medium-power neutron source. The present project, "Phase Space Transformer for UCN", is meant to design, construct and test a prototype for such efficient production of highly monochromatised cold and very cold neutrons (VCN) by the method of phase space transformation (PST) of ultra-cold neutrons (UCN) . At the planned UCN source at PSI (20 µA average proton current) a performance as that of FOCUS/SINQ could be reached. The unique capability for PST-UCN is however in the Very Cold Neutrons (VCN) regime, enabling measurements of S(q,w) in a range not accessible by existing instruments. The corresponding length and time scales match those relevant for nanostructures and for very slow dynamics in surfaces and interfaces. This project presents a first necessary step towards the design of a world-wide unique neutron scattering instrument at the PSI UCN source.

Results
Significant intensity gains can be realized by accelerating ultra cold neutrons to higher energy by using the Doppler effect. The concept for experiments planned for April 2008 at the ILL have been worked out with the help of a company being specialised in spin-testing devices. First centrifugal tests and characterisations with intercalated graphite have been performed. It is planned using phase space transformation at future UCN-sources to improve the neutron flux for scattering experiments.