The neutron EDM experiment at the ILL

The latest-generation neutron electric dipole moment (EDM) experiment has been collecting data at the ILL since 1996. It uses a “cohabiting” atomic-mercury magnetometer to measure and compensate for the magnetic field fluctuations that were the principal source of systematic errors in previous experiments. The first results, which are soon to be published, essentially verify the existing limit on the dipole moment d n ; however, this new measurement is clearly limited by statistical rather than systematic uncertainties.