Neutron Spin Echo Spectrometers of the Next Generation — Where Are the Limits?

Monkenbusch, M.

doi:10.1007/3-540-45823-9_16

Cited by 3 publications

(5 citation statements)

References 4 publications

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“…For each Q the data are normalized by measuring graphite as the resolution sample with equal count statistics like that of the sample. Details of NSE measurement techniques can be found elsewhere. ,, …”

Section: Methodsmentioning

confidence: 99%

Protein Entrapment in Polymeric Mesh: Diffusion in Crowded Environment with Fast Process on Short Scales

et al. 2016

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The natural environment of proteins is a crowded environment as in cells, extracellular fluids, or during processing. Semidilute polymer solutions have been a source of rich structural and dynamical properties and mimic a crowded environment, but a proper understanding of protein dynamics in the crowded environment is far lagging. Such a study not only realizes protein's natural environment in a crowded solution in the cell or during processing but also manifests the underlying protein−polymer interaction. By dispersing model globular proteins like α-lactalbumin (La) and hemoglobin (Hb), in aqueous solution of poly(ethylene oxide) (PEO) we mimic a crowded environment and use state-of-the-art neutron spin echo (NSE) and small-angle neutron scattering (SANS) techniques to observe the corresponding protein dynamics in semidilute polymer solution. NSE can access the fast diffusion process (D fast ) prior to the slow diffusion process on long times and length scales (D γ ). The protein dynamics in a crowded environment can be described analogous to the diffusion in a periodic potential. The fast dynamics corresponds to diffusion inside a trap built by the polymer mesh while the slower process is the long time diffusion on macroscopic length scales also observed by other techniques. We observe the onset of fractional diffusion for higher concentrated polymer solutions.

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Section: Methodsmentioning

confidence: 99%

Protein Entrapment in Polymeric Mesh: Diffusion in Crowded Environment with Fast Process on Short Scales

et al. 2016

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“…The emerging shape of the magnetic field somehow resembles a smoothed version of the piecewise combination of the parabolic shapes of equation (11) with the cusp at the tip of the triangle. The degree of cusp smoothing obviously represents the compromise between the zero contribution of the pure parabola shape and the large additional term caused by the naked cusp.…”

Section: Optimum Shapes For Low Inhomogeneity: An Analytic Approachmentioning

confidence: 99%

“…figure 1) are sufficient to correct for all field integral inhomogeneities of an arrangement of ideal cylindrical solenoids [9]. If their axial positions are carefully selected/adjusted in practice two correctors can be sufficient [10,11]. In particular this holds since at the moment the technical ability to realize the correcting current distributions with the required accuracy is limited.…”

Section: Introductionmentioning

confidence: 99%

Optimized superconducting coils for a high-resolution neutron spin-echo spectrometer at the European Spallation Source, ESS

Pasini¹,

Monkenbusch²

2015

Meas. Sci. Technol.

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The ultimate energy resolution in inelastic thermal neutron scattering spectroscopy is provided by neutron spin echo (NSE) spectrometers. The characteristic of a NSE spectrometer is that it detects neutron-velocity changes by spin-coding. It measures the intermediate scattering function I(Q, t) in terms of final beam polarisation. High resolution in that case means the extension of the Fourier time (t) range towards 1 µs. The most important technical limitation to increase the resolution of NSE spectrometers results from the need to equalize the field integrals that determine the coding spin-precession angles along different neutron paths by combining a suitable precession field with correction coils. Here we report on the field shape optimisation and design of precession magnetic coil arrangements with minimal intrinsic field integral inhomogeneity for a wide and diverging neutron beam with a new semi-analytical approach and a numerical method. This minimizes the amount of additionally required correction. The solenoid configuration we found fulfils all the conditions required by a real NSE spectrometer.

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“…. Q 24 [2]. For a source with a given repetition frequency the intensity gain factor can only be increased by reducing the moderator detector distance, e.g.…”

Section: Tof Wavelength Managementmentioning

confidence: 99%

“…The width of the usable wavelength frame between two pulses Dl # 1=nL D h=m n with h=m n ¼ 395:6 £ 10 29 m 2 =s is inversely proportional to the moderator detector distance L D and the pulse repetition frequency n and independent from the chosen wavelength band. Compared to a sequence of experiments at a continuous source the gain factor is [2] g ¼ ln l max l min =ðD FWHM l=lÞ:…”

Section: Tof Wavelength Managementmentioning

confidence: 99%