RESPECT: Neutron Resonance Spin-Echo Spectrometer for Extreme Studies

TL;DR

RESPECT is a novel neutron resonance spin-echo spectrometer designed for extreme studies, capable of exploring a wide dynamic range and suitable for various non-dispersive processes, with improved intensity and flexibility over existing techniques.

Contribution

It introduces a new design of neutron spin-echo spectrometer with enhanced dynamic range, higher intensity, and versatility, including a MIEZE mode for depolarizing environments.

Findings

Dynamic range can be varied over 8 orders of magnitude.

Spin echo times up to 1 microsecond are achievable.

Expected intensity gains of at least one order of magnitude.

Abstract

We propose the design of a Resonance SPin-echo spECtrometer for exTreme studies, RESPECT, that is ideally suited for the exploration of non-dispersive processes such as diffusion, crystallization, slow dynamics, tunneling processes, crystal electric field excitations, and spin fluctuations. It is a variant of the conventional neutron spin-echo technique (NSE) by i) replacing the long precession coils by pairs of longitudinal neutron spin-echo coils combined with RF-spin flippers and ii) by stabilizing the neutron polarization with small longitudinal guide fields that can in addition be used as field subtraction coils thus allowing to adjust the field integrals over a range of 8 orders of magnitude. Therefore, the dynamic range of RESPECT can in principle be varied over 8 orders of magnitude in time, if neutrons with the required energy are made available. Similarly as for existing NSE-spectrometers, spin echo times of up to approximately 1 microsecond can be reached if the divergence and the correction elements are properly adjusted. Thanks to the optional use of neutron guides and the fact that the currents for the correction coils are much smaller than in standard NSE, intensity gains of at least one order of magnitude are expected , making the concept of RESPECT also competitive for operation at medium flux neutron sources. RESPECT can also be operated in a MIEZE configuration allowing the investigation of relaxation processes in depolarizing environments as they occur when magnetic fields are applied at the sample position, i.e. for the investigation of the dynamics of flux lines in superconductors, magnetic fluctuations in ferromagnetic materials, and samples containing hydrogen.