Producing ultracold neutrons with a spallation source and superfluid helium*

An electric dipole moment of the neutron large enough to detect with current techniques would be an indication of CP-violating processes beyond the standard model of particle physics and could explain the matter-antimatter asymmetry in the universe.

The goal of the TUCAN collaboration is to measure the neutron electric dipole moment with a sensitivity of 10^-27 ecm. To achieve the necessary statistical sensitivity, we are designing the TRIUMF UltraCold Advanced Neutron (TUCAN) source, a next-generation source for ultracold neutrons based on a spallation target and a superfluid-helium converter. To this end, we recently completed the installation of a prototype source at a new, dedicated beamline at TRIUMF.

This presentation will show results from a comprehensive test run of the prototype source, compare them to simulations, and show how we use the simulations to optimize neutron moderators for the next-generation source to achieve a several orders of magnitude higher ultracold-neutron flux.