Neutron phase spin echo

TL;DR

This paper introduces a new neutron spin resonance technique based on neutron spin echo, achieving unprecedented energy resolution and promising significant advancements in fundamental neutron physics and scattering applications.

Contribution

It presents a novel neutron spin resonance method with high precision and potential for substantial improvements in energy resolution over existing techniques.

Findings

Achieved a velocity change resolution of 4×10⁻⁷

Demonstrated energy resolution better than 3 neV

Projected improvements could reach 10 peV energy resolution

Abstract

A novel neutron spin resonance technique is presented based on the well-know neutron spin echo method. In a first proof-of-principle measurement using a monochromatic neutron beam, it is demonstrated that relative velocity changes of down to a precision of $4 \times 10^{-7}$ can be resolved, corresponding to an energy resolution of better than 3~neV. Currently, the sensitivity is only limited by counting statistics and not by systematic effects. An improvement by another two orders of magnitude can be achieved with a dedicated setup, allowing for energy resolutions in the 10~peV regime. The new technique is ideally suited for investigations in the field of precision fundamental neutron physics, but will also be beneficial in scattering applications.