Comparison of ultracold neutron sources for fundamental physics measurements

TL;DR

This paper compares the performance of leading ultracold neutron sources used in fundamental physics experiments, focusing on UCN density and suitability for precision measurements like the neutron electric dipole moment search.

Contribution

It provides an experimental comparison of major UCN sources using a standard storage bottle to evaluate their UCN densities for fundamental physics applications.

Findings

Compared UCN densities at different sources

Assessed suitability for nEDM experiments

Identified optimal UCN sources for future research

Abstract

Ultracold neutrons (UCNs) are key for precision studies of fundamental parameters of the neutron and in searches for new CP violating processes or exotic interactions beyond the Standard Model of particle physics. The most prominent example is the search for a permanent electric dipole moment of the neutron (nEDM). We have performed an experimental comparison of the leading UCN sources currently operating. We have used a 'standard' UCN storage bottle with a volume of 32 liters, comparable in size to nEDM experiments, which allows us to compare the UCN density available at a given beam port.