Characterization of the new Ultracold Neutron beamline at the LANL UCN facility

TL;DR

This paper details the characterization of a new ultracold neutron beamline at LANL, including measurements of UCN storage, transport, and an analytical model of the UCN energy spectrum, supporting the LANL nEDM experiment.

Contribution

It introduces a new UCN beamline at LANL, with measurements and an analytical model that enable the experiment to reach its targeted sensitivity.

Findings

Sufficient stored polarized UCN for nEDM sensitivity of 2×10⁻²⁷ e·cm in 5 years

Successful measurement of UCN storage and transport during commissioning

Development of an analytical model for the UCN energy spectrum

Abstract

The neutron electric dipole moment (nEDM) experiment that is currently being developed at Los Alamos National Laboratory (LANL) will use ultracold neutrons (UCN) and Ramsey's method of separated oscillatory fields to search for a nEDM. In this paper, we present measurements of UCN storage and UCN transport performed during the commissioning of a new beamline at the LANL UCN source and demonstrate a sufficient number of stored polarized UCN to achieve a statistical uncertainty of $\delta d_n = 2\times 10^{-27}$~$e\cdot\text{cm}$ in 5 calendar years of running. We also present an analytical model describing data that provides a simple parameterization of the input UCN energy spectrum on the new beamline.