The cryoEDM experiment was formed to further improve the neutron EDM limit set by nEDM, and maybe measure a non-zero value. The improvement in sensitivity will be achieved by producing, storing and detecting ultra-cold neutrons (UCN) inside superfluid helium. This allows a greater number of UCN to be produced by down-scattering a cold neutron beam. A further improvement comes from operating at a higher electric field which can be achieved in the superfluid.

Operating the experiment at cryogenic temperatures introduces significant technical challenges. We need to fill a 250 litre volume with superfluid helium and hold it at 0.5K. The mercury magnetometer used by the nEDM experiment will no longer work. Therefore a SQUID magnetometer has been developed by the Oxford group and installed in the cryoEDM apparatus.

The project is a collaboration between: The Rutherford Appleton Laboratory; Sussex; Oxford; Kure, Japan; and the Institut Laue-Langevin, Grenoble, where the experiment is located. CryoEDM aims to reach a sensitivity of 10^-28 ecm, which will constrain many particle physics theories, especially supersymmetry, which in turn, has helped set limits on dark matter.

More information can be found on the collaboration homepage: http://www.cryoEDM.org.