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

A spallation target at TRIUMF for fundamental neutron physics

Ultracold neutrons (UCNs) are a powerful tool for probing the Standard Model at high precision. The TRIUMF Ultracold Advanced Neutron (TUCAN) collaboration is building a new UCN source to provide unprecedented densities of UCNs for experiments. This source will use a tantalum-clad tungsten spallation target, receiving up to 40 µA of 480-MeV protons from TRIUMF’s main cyclotron. The beamline and target were constructed from 2014 to 2016 and operated at beam currents up to 10 µA from 2017 to 2019 as part of a prototype UCN source. We describe the design choices for the target and target-handling system, as well as our benchmarking of the target performance using UCN production measurements