Magnetometry at the fTesla-scale for neutron EDM experiments using a co-habiting Xenon magnetometer based on free spin precession

Novel neutron EDM experiments, like the international neutron EDM collaboration at the Paul Scherrer Institute (PSI) aim to reach a measurement sensitivity of ≈ 10-28 ecm, a two orders of magnitude improvement compared to the present upper limit of dn < 3 x 10-26 e∙cm for the neutron electric dipole moment (nEDM). In order to reach this ambitious goal, magnetometry reaching the 1 fT sensitivity level during a typical Ramsey cycle of 200s is demanded. In this proposal we concentrate on the development of a Xenon magnetometer which should be able to monitor and correct geometric phase induced false nEDM effects. These false effects, which set the present systematic limit of dn, false ≈ 10-26ecm, result from the interaction of the well known vxE-field with magnetic field gradients and produce a frequency shift linear to the electric field mimicking an nEDM. This frequency shift can be measured using the Ramsey method of separated oscillatory fields. Spin-polarized Xenon is produced by optical pumping and the free precession of nuclear spins (co-habiting atomic Xenon magnetometer) is monitored within the ultracold neutron (UCN) storage volume of the nEDM spectrometer.

DFG Programme Priority Programmes

Subproject of SPP 1491:  Precision Experiments in Particle- and Astrophysics with Cold and Ultracold Neutrons