Estimated performance of the TRIUMF ultracold neutron source and electric dipole moment apparatus

Searches for the permanent electric dipole moment of the neutron (nEDM) provide strong constraints on theories beyond the Standard Model of particle physics. The TUCAN collaboration is constructing a source for ultracold neutrons (UCN) and an apparatus to search for the nEDM at TRIUMF, Vancouver, Canada. In this work, we estimate that the spallation-driven UCN source based on a superfluid helium converter will provide $(1.38\pm0.02) \times 10^7$ polarized UCN at a density of $217\pm3$~UCN/cm$^3$ to a room-temperature EDM experiment per fill. With $(1.51\pm0.02) \times 10^6$ neutrons detected after the Ramsey cycle, the statistical sensitivity for an nEDM search per storage cycle will be $(1.94\pm0.06) \times 10^{-25}\,e$cm (1$\sigma$). The goal sensitivity of $10^{-27}\,e$cm (1$\sigma$) can be reached within $280\pm16$ measurement days.Comment: Proceedings submitted to EPJ Web of Conferences for the Symposium on Symmetries in Subatomic Physics (SSP2022

Study of Thin Iron Films for Polarization Analysis of Ultracold Neutrons

The TUCAN (TRIUMF Ultra-Cold Advanced Neutron) collaboration aims to search for the neutron electric dipole moment (nEDM) with unprecedented precision. One of the essential elements for the nEDM measurement is a polarization analyzer of ultracold neutrons (UCNs), whose main component is a magnetized thin iron film. Several thin iron films were deposited on aluminum and silicon ubstrates and were characterized by vibrating sample magnetometry and cold-neutron reflectometry. A magnetic field required to saturate the iron film is $\sim$12 kA/m for those on the aluminum substrates and 6.4 kA/m for the silicon substrates. The magnetic potential of the iron films on the Si substrate was estimated to be 2 T by the neutron reflectometry, which is sufficient performance for an UCN polarization analyzer of the nEDM measurement.Comment: Proceedings of the 24th International Spin Symposium (SPIN 2021), 18-22 October 2021, Matsue, Japa

The Precision nEDM Measurement with UltraCold Neutrons at TRIUMF

The TRIUMF Ultra-Cold Advanced Neutron (TUCAN) collaboration aims at a precision neutron electric dipole moment (nEDM) measurement with an uncertainty of $10^{-27}\,e\cdot\mathrm{cm}$, which is an order-of-magnitude better than the current nEDM upper limit and enables us to test Supersymmetry. To achieve this precision, we are developing a new high-intensity ultracold neutron (UCN) source using super-thermal UCN production in superfluid helium (He-II) and a nEDM spectrometer. The current development status of them is reported in this article.Comment: Proceedings of the 24th International Spin Symposium (SPIN 2021), 18-22 October 2021, Matsue, Japa