References of "Konter, J. A"
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See detailCharacterisation of the polarised neutron beam at the small angle scattering instrument SANS-I with a polarised proton target
Aswal, V. K.; van den Brandt, B.; Hautle, P. et al

in Nuclear Instruments & Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment (2008), 586

A transmission neutron polariser (Fe/Si supermirror) has been successfully implemented in the small angle neutron scattering instrument SANS-I at the SINQ neutron source. The polariser is needed for ... [more ▼]

A transmission neutron polariser (Fe/Si supermirror) has been successfully implemented in the small angle neutron scattering instrument SANS-I at the SINQ neutron source. The polariser is needed for investigations of magnetic nanostructures as well as for spin contrast variation techniques relying on the spin-dependent neutron scattering length of polarised nuclei. The V-shaped polariser is installed in the first section of the collimator system of the SANS instrument and its performance is optimised for neutrons with a wavelength between 0.5 and 1.0 nm. For a precise polarisation analysis of a beam with selectable incident divergence, such as in SANS experiments, an opaque spin filter is ideal. We used a solid polarised proton target exploiting the strong spin-dependent neutron scattering cross-section of hydrogen and determined the neutron beam polarisation to a precision of 0.5% for different collimations in a broad wavelength band. [less ▲]

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See detailCreating local contrast in small-angle neutron scattering by dynamic nuclear polarization
van den Brandt, B.; Glattli, H.; Hautle, P. et al

in Journal of Applied Crystallography (2007), 40(s), 106-110

Low-resolution small-angle neutron scattering measurements can benefit from polarized protons to generate scattering contrast profiles. In a recently developed technique, time-resolved polarized SANS ... [more ▼]

Low-resolution small-angle neutron scattering measurements can benefit from polarized protons to generate scattering contrast profiles. In a recently developed technique, time-resolved polarized SANS tries to make use of spatial polarization gradients created around paramagnetic centres at the onset of dynamic nuclear polarization. The time constants which describe the build-up of polarization around the paramagnetic centre and the subsequent diffusion of polarization in the solvent were determined by analysing the temporal evolution of the nuclear polarization. The possible use and the limitations of this technique as a spectroscopic tool are discussed. [less ▲]

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See detailTime-resolved nuclear spin-dependent small-angle neutron scattering from polarised proton domains in deuterated solutions
van den Brandt, B.; Glättli, H.; Grillo, I. et al

in European Physical Journal B -- Condensed Matter (2006), 49(2), 157-165

We have investigated the process of dynamic proton polarisation by means of time-resolved polarised small-angle neutron scattering (SANS) on frozen solutions of EHBA-CrV molecules in glycerol-water ... [more ▼]

We have investigated the process of dynamic proton polarisation by means of time-resolved polarised small-angle neutron scattering (SANS) on frozen solutions of EHBA-CrV molecules in glycerol-water mixtures as a function of the concentration of EHBA-CrV and for different degrees of deuteration of the solvent. In the EHBA-CrV complex, the spins of the 20 protons which surround the paramagnetic CrV can be oriented using the method of dynamic nuclear polarisation (DNP), thereby offering the possibility to create locally a nuclear spin-dependent contrast for SANS. The time constants which describe the build-up of polarisation around the paramagnetic centre and the subsequent diffusion of polarisation in the solvent were determined by analysing the temporal evolution of the nuclear polarisation, which in turn was obtained by fitting a core-shell model to the time-dependent SANS curves. The results on the spin dynamics obtained using the scattering function of a core-shell could be independently confirmed by evaluating the integrated SANS intensity. A thermodynamic one-centre model is presented which is able to reproduce the observed dependence of the proton polarisation times on the proton concentration of the solvent. [less ▲]

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See detailHigh-accuracy measurement of the spin-dependent neutron scattering length of the deuteron
van den Brandt, B.; Hautle, P.; Kohlbrecher, J. et al

in Proceedings of the 16th International Spin Physics Symposium and Workshop on Polarized Electron Sources and Polarimeters (2005)

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See detailProduction of ultracold neutrons from a cold neutron beam on a 2H2 target
Atchison, F.; van den Brandt, B.; Brys, T. et al

in Physical Review. C : Nuclear Physics (2005), 71

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See detailAn experimental approach to the dynamics of nuclear polarisation
van den Brandt, B.; Glättli, H.; Grillo, I. et al

in Nuclear Instruments & Methods in Physics Research Section A (2004), 526

In the past 3 years a series of experiments have shed new light on the mechanism of dynamic nuclear polarisation (DNP). Time-resolved polarised small-angle neutron scattering and nuclear magnetic ... [more ▼]

In the past 3 years a series of experiments have shed new light on the mechanism of dynamic nuclear polarisation (DNP). Time-resolved polarised small-angle neutron scattering and nuclear magnetic resonance have been used simultaneously to study the nuclear polarisation build-up around paramagnetic centres during DNP. This approach, which aims at visualising the nuclear polarisation process on a microscopic scale, shall be exemplified and the experimental techniques used described in some detail. [less ▲]

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