Towards TUCAN's Search for the Neutron Electric Dipole Moment

Abstract

The TRIUMF ultracold advanced neutron (TUCAN) collaboration is a transpacific collaboration with the objective to measure the neutron electric dipole moment. We aim for an unprecedented sensitivity of $10^{-27}\,e$cm, an improvement by a factor of 30 over the current upper limit for this elusive quantity. To achieve this goal, we are planning a next-generation source for ultracold neutrons, based on a new, dedicated neutron spallation source at TRIUMF, liquid deuterium as cold moderator, and superfluid helium as ultracold-neutron converter. To operate at the full beam power of 20$\,$kW, a $^3$He fridge will provide a cooling power of 10$\,$W at 0.8$\,$K, cooling the converter to a temperature of 1.1$\,$K.