Neutron resonance spin-echo upgrade at the three-axis spectrometer FLEXX

Groitl, Felix; Keller, T.; Quintero-Castro, D. L.; Habicht, K.

doi:10.1063/1.4908167

Cited by 15 publications

(12 citation statements)

References 43 publications

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“…In the late eighties, R. Golub and R. Gähler have proposed an alternative design to solenoid-based NSE spectrometers, relying on the use of compact radio-frequency spin flippers (RFSF) and hence termed Neutron Resonance Spin Echo (NRSE) [6]. NRSE is now available at different instruments throughout the world (MUSES [7] at LLB-Saclay and IN22-ZETA [8] at ILL-Grenoble in France, RESEDA [9] and TRISP [10] at MLZ-Garching, V2-FLEXX [11] at BER II-Berlin in Germany, VIN ROSE [12] at J-PARC/MLF in Japan) and has opened new experimental perspectives by pushing the usual resolution limits of inelastic scattering [13][14][15] and diffraction [16,17]. As noticed in the early stages of the development of NRSE, series of resonant neutron spin flips can used as building blocks for alternative spectroscopic methods, in analogy with pulse sequences employed in nuclear magnetic resonance (NMR).…”

Section: Principles and Limits Of Mieze Spectroscopymentioning

confidence: 99%

On the resolution of a MIEZE spectrometer

Martín

2018

Nuclear Instruments and Methods in Physics Research Section A:

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We study the effect of a finite sample size, beam divergence and detector thickness on the resolution function of a MIEZE spectrometer. We provide a transparent analytical framework which can be used to determine the optimal trade-off between incoming flux and time resolution for a given experimental configuration. The key result of our approach is that the usual limiting factor of MIEZE spectroscopy, namely neutron path length differences throughout the instrument, can be suppressed up to relatively large momentum transfers by using a proper small-angle (SANS) geometry. Under such configuration, the hitherto accepted limits of MIEZE spectroscopy in terms of time-resolution are pushed upwards by typically an order of magnitude, giving access to most of the topical fields in soft- and hard-condensed matter physics.Comment: 19 pages, 6 figure

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Section: Principles and Limits Of Mieze Spectroscopymentioning

confidence: 99%

On the resolution of a MIEZE spectrometer

Martín

2018

Nuclear Instruments and Methods in Physics Research Section A:

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“…Neutron resonance spin echo (NRSE) [2,3], a variation of classical NSE, replaces the long solenoids which generate the precession fields with compact resonant spin flippers. This allows to adapt the technique for various science cases [4][5][6]. Modulation of IntEnsity with Zero Effort (MIEZE), being such a modification, is insensitive to depolarizing (e.g.…”

Section: Introductionmentioning

confidence: 99%

The software package MIEZEPY for the reduction of MIEZE data

et al. 2019

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Modulation of intensity with zero effort (MIEZE) is a neutron resonant spin echo technique which allows to measure the intermediate scattering function S(Q, τ) under depolarizing conditions. Since MIEZE produces a complex four dimensional dataset, we have developed the software package MIEZEPY to reduce the dataset and extract S(Q, τ) in a user friendly manner. This is an essential step in establishing the MIEZE technique and improving user operation. MIEZEPY was written in Python as an open source package and was developed on GitHub. In this paper the framework and implementation of this package as well as the physical and mathematical principles underlying the data reduction procedure will be introduced to lay out the complexity of this task.

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“…Up to now, LD has been implemented and routinely operated on the beamlines of TRISP (FRM II, MLZ) 1 , FLEXX (BER-II, HZB) 7 and ZETA (ILL) 8 , with a relative resolution of Δ d / d ~10 −6 . Instead of using two static magnetic fields, these instruments use four, short radio-frequency (RF) neutron spin flippers 9 constructed using aluminium wires to minimize parasitic scattering.…”

Section: Introductionmentioning

confidence: 99%

High resolution neutron Larmor diffraction using superconducting magnetic Wollaston prisms

Feng

Thaler

et al. 2017

Sci Rep

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The neutron Larmor diffraction technique has been implemented using superconducting magnetic Wollaston prisms in both single-arm and double-arm configurations. Successful measurements of the coefficient of thermal expansion of a single-crystal copper sample demonstrates that the method works as expected. The experiment involves a new method of tuning by varying the magnetic field configurations in the device and the tuning results agree well with previous measurements. The difference between single-arm and double-arm configurations has been investigated experimentally. We conclude that this measurement benchmarks the applications of magnetic Wollaston prisms in Larmor diffraction and shows in principle that the setup can be used for inelastic phonon line-width measurements. The achievable resolution for Larmor diffraction is comparable to that using Neutron Resonance Spin Echo (NRSE) coils. The use of superconducting materials in the prisms allows high neutron polarization and transmission efficiency to be achieved.The ability of conventional neutron diffraction to measure precise values of the d-spacings of crystalline materials is limited by factors such as the strength of the available neutron source and the practical length of neutron flight paths. The current limit is around Δd/d of 10 −3 . At reactor neutron sources however, high resolution measurements of Δd/d ~ 10 −6 have been achieved using the Larmor diffraction (LD) technique 1 first introduced by Rekveldt 2 . Like the neutron spin echo (NSE) technique proposed by Mezei 3 for energy encoding, the LD method makes use of Larmor precession of neutron spins in well-defined magnetic fields. The method allows the lattice spacing of the diffracting crystal to be encoded into the Larmor phase of the neutron spin by making this phase depend only on the scattering vector of the diffracting Bragg peak, a quantity that is independent of the monochromaticity and collimation of the neutron beam. This enables small changes of the lattice spacing to be measured through the change of the neutron Larmor phase instead of by measuring the change in the diffraction angle.The original Rekveldt proposal for LD involved magnetic fields before and after the sample. When the field boundaries of these two magnetic fields are aligned parallel to the crystal diffraction plane, all the diffracted neutrons will yield the same Larmor phase regardless their incident angle on the sample. Therefore, the Larmor phase of the diffracted neutrons will only depend on the geometry and intensities of the magnetic fields before and after the sample.The LD method has been used in a number of experiments and its recent applications have been summarized by Rekveldt 4 including absolute lattice spacing determination 5 and temperature induced lattice variations 6 . Up to now, LD has been implemented and routinely operated on the beamlines of TRISP (FRM II, MLZ) 1 , FLEXX (BER-II, HZB) 7 and ZETA (ILL) 8 , with a relative resolution of Δd/d ~10 −6 . Instead of using two static magnetic fields, these...

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Neutron resonance spin-echo upgrade at the three-axis spectrometer FLEXX

Cited by 15 publications

References 43 publications

On the resolution of a MIEZE spectrometer

On the resolution of a MIEZE spectrometer

The software package MIEZEPY for the reduction of MIEZE data

High resolution neutron Larmor diffraction using superconducting magnetic Wollaston prisms

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