The first improvement of the cryogenic neutron EDM experiment is the new production method for ultra-cold neutrons (UCN). Ultra-cold neutrons are created through a 'downscattering' process, where they lose almost all their enegy as they collide with a helium atom within superfluid liquid helium. Production rates of (0.91± 0.13) UCN/cm 3 /sec from a beam of 2.6 x 10 7 n/cm 2 /s/Å at 8.9 Å have been observed, which are very close to the expected values of UCN production via this downscattering process.

With this new ultra-cold neutron production technique, we are confident that using the current neutron beam at the ILL, as used in the room temperature EDM experiment, UCN production density will be 50 times higher than the previous experiment.

After their time in the neutron containment bottle, the ultra-cold neutrons are then detected, using special solid-state detectors, especially developed for use within liquid helium. One of these detectors is shown below.