Neutron Spin‐Echo Instrumentation for Magnetic Scattering

Keller, T.; Trepka, Heiko; Habicht, Klaus; Keimer, B.

doi:10.1002/pssb.202100164

Cited by 4 publications

(2 citation statements)

References 85 publications

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“…The insensitivity to spin flips facilitates the study of samples containing hydrogen, which shows strong spin -incoherent scattering. While the study of spin excitations is a successful domain of classical NSE [33], and the study of ferromagnets is in principle possible in the 'ferromagnetic NSE configuration', it requires additional polarizers up-and downstream the sample leading to a strong loss of the signal intensity. Especially for ferromagnets, MIEZE has proven to be a powerful alternative [17,27].…”

Section: Introductionmentioning

confidence: 99%

Extending MIEZE spectroscopy towards thermal wavelengths

Jochum¹,

Keller²,

Pfleiderer³

2022

Preprint

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We propose a Modulation of intensity with zero effort (MIEZE) setup for high -resolution neutron spectroscopy at momentum transfers up to 3 Å−1 ,energy transfers up to 20 meV, and an energy resolution in the µeVrange using both thermal and cold neutrons. MIEZE has two prominent advantages compared to classical neutron spin -echo. The first one is the possibility to investigate spin -depolarizing samples or samples in strong magnetic fields without loss of signal amplitude and intensity. This allows for the study of spin fluctuations in ferromagnets, and facilitates the study of samples with strong spin -incoherent scattering. The second advantage is that multi -analyzer setups can be implemented with comparatively small effort. The use of thermal neutrons increases the range of validity of the spin -echo approximation towards shorter spin -echo times. In turn, the thermal MIEZE option for greater ranges (TIGER) closes the gap between classical neutron spin -echo spectroscopy and conventional highresolution neutron spectroscopy techniques such as triple -axis, time -offlight, and back -scattering. To illustrate the feasibility of TIGER we present the details of an implementation at the beamline RESEDA at FRM II by means of an additional velocity selector, polarizer and analyzer.

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Section: Introductionmentioning

confidence: 99%

Extending MIEZE spectroscopy towards thermal wavelengths

Jochum¹,

Keller²,

Pfleiderer³

2022

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…The insensitivity to spin flips facilitates the study of samples containing hydrogen, which show strong spinincoherent scattering. The study of spin excitations is a successful domain of NSE-TAS (Keller et al, 2022). Though the study of ferromagnets is, in principle, possible with Mezei's 'ferromagnetic NSE configuration', it requires additional polarizers upstream and downstream of the sample, leading to a strong loss of the signal intensity.…”

Section: Introductionmentioning

confidence: 99%

Extending MIEZE spectroscopy towards thermal wavelengths

Jochum¹,

Keller²,

Pfleiderer³

2022

J Appl Cryst

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A modulation of intensity with zero effort (MIEZE) setup is proposed for high-resolution neutron spectroscopy at momentum transfers up to 3 Å−1, energy transfers up to 20 meV and an energy resolution in the microelectronvolt range using both thermal and cold neutrons. MIEZE has two prominent advantages compared with classical neutron spin echo. The first is the possibility to investigate spin-depolarizing samples or samples in strong magnetic fields without loss of signal amplitude and intensity. This allows for the study of spin fluctuations in ferromagnets, and facilitates the study of samples with strong spin-incoherent scattering. The second advantage is that multi-analyzer setups can be implemented with comparatively little effort. The use of thermal neutrons increases the range of validity of the spin-echo approximation towards shorter spin-echo times. In turn, the thermal MIEZE option for greater ranges (TIGER) closes the gap between classical neutron spin-echo spectroscopy and conventional high-resolution neutron spectroscopy techniques such as triple-axis, time-of-flight and back-scattering. To illustrate the feasibility of TIGER, this paper presents the details of its implementation at the RESEDA beamline at FRM II by means of an additional velocity selector, polarizer and analyzer.

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Conceptual study of a new instrument for dynamic neutron scattering measurements—The modulated intensity with diffraction analysis spectrometer (MIDAS)

Benedetto,

Kearley,

Faraone

2024

Review of Scientific Instruments

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Dynamic neutron scattering probes unique nanoscale dynamics via measurement of energy exchanged between a sample and the neutrons. The two spectrometers that investigate processes with characteristic times around a nanosecond are backscattering (BS) and neutron spin-echo (NSE). We present a new method for measuring dynamics using an oscillating cosine-like energy-distribution neutron-package at the sample and measure solely the portion scattered into the elastic line. This portion corresponds to elastically scattered neutrons and, in addition, inelastic components that are scattered with a probability directly proportional to the cosine Fourier-coefficients of the exchanged-energy spectrum. The counts at the detector thus correspond to the van Hove intermediate scattering function. We denote this new method as “Fourier transform neutron scattering” (FTNS), it being broadly analogous to IR and Raman spectroscopies. Here, the realization of such a concept is investigated using an oscillating incident beam produced via a precession method and a secondary spectrometer identical to a BS instrument using crystal analyzers. The instrument is denoted “Modulated Intensity with Diffraction Analysis Spectrometer” (MIDAS). However, simpler approaches, e.g., choppers, may also be used for an FTNS instrument. The theory behind MIDAS is presented, supported by numerical calculations and in silico experiments. Finally, we present a Monte Carlo simulation to compare BS and MIDAS spectrometers. This shows that MIDAS has almost 100 times more incident flux than standard BS, but due to the better signal-to-noise ratio of BS, the final information acquisition rate gain of MIDAS is approximately a factor of 2.

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Neutron Spin‐Echo Instrumentation for Magnetic Scattering

Cited by 4 publications

References 85 publications

Extending MIEZE spectroscopy towards thermal wavelengths

Extending MIEZE spectroscopy towards thermal wavelengths

Extending MIEZE spectroscopy towards thermal wavelengths

Conceptual study of a new instrument for dynamic neutron scattering measurements—The modulated intensity with diffraction analysis spectrometer (MIDAS)

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