neutron scattering at the budapest neutron centre

Neutron Scattering at the Budapest Neutron Centre

MTEST: Material Testing Diffractometer

The Ordela 1200N position sensitive detector has been installed at the MTEST diffractometer.Actually it is in regular operation.

Ni pattern recorded with 1.45A°neutrons in “near” configuration

Detector in “far” position

Total (Bragg and diffuse) scattering measurements on powder, liquid and amorphous materials. A four-circle goniometer provides conditions for texture measurements.

PSD: Powder Diffractometer

Amorphous materials

borosilicate glasses: suitable materials for the

storage of high-level radioactive waste materials

boromolybdate glasses: important physical and

chemical properties, large ion- and electron

conductivity, catalytic activity, non-linear optical

properties, mechanical resistance

mixed alkali silicate-bioactive glasses: in contact

with body fluids, glasses induce a specific

biological response at their surface

chalcogenide glasses: wide area of application as electrical and optical components, semiconductors...

Temperature and pressure interval:

TiZr cell: Tmax: 450°C pmax: 300 bar

Saphire cell: Tmax: 950°C pmax: 300 bar

Study of CO2 capture in supercritical conditions

- Neutron diffraction study of thermal phase stability (exp. Alloys)

- Neutron diffraction in temperature dependent deformation

(crystallization, new texture)

- Neutron diffraction study on electrode materials (based on Li or Ni

elements)-Characterization of nanostructured alloys in extreme environment

New in-situ sample environment high temperature pressure cell has

been developed.

PSD: Powder Diffractometer

TOF: Time-of-Flight Diffractometer

Installed on a radial thermal neutron beam in a new guide-hall. The main advantage of TOF monochromatization in neutron diffractometry on a continuous source is the variable resolution and intensity. A full diffraction spectrum can be gained within a variable bandwidth with ultrahigh resolution or high intensity at conventional resolutions.


New detector and data acquisition system has been installed and commissioned

Backscattering detector bank:•2θ = 144°-165°•72-88 3He tubes•Optimized for HR diffraction

Lower angle detector bank:•2θ = 120°, 90°, 60°•24 3He tubes•Extension of Q-range

Common, List mode DAQ


Construction of the backscattering bank

Tube size: 300x30x15mm (squashed)Pressure of 3He: 3barEfficiency: 75% at 4Å – 30% at 1Å7 boxes in 3 rows, +1Boxes can individually be aligned in two directionTubes will be aligned within the box for time-focusing.The positions and the orientation of the tubes can easily be calculated - even if the bank is replaced.The lower angle bank is similar, but 2 boxes in 3 rows.


Optimization of the backscattering bank

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543210-1

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x10-3

Colors: available Δd [Å] White lines: constant d(t) surfaces – time focusingPositions in m, the sample is in the origo.

•Compromising between resolution and detector solid angle.

•Aligning the tubes individually, Δd<2x10-3Å resolution can be kept for almost the entire detector bank.

•Intensity gain > 10

•Solid angle: x 17

•Resolution improves: 1.5x10-3Å at higher angles.


Positioner for large samples

• Precession and nutation about the beam axis are provided, rotation can be added later;

• Nutaion frame plane offset to allow free access to and scattered beam extraction from the nutation axis;

• Large free solid angle for backscattering experiments.

TOF

Simulation of Wavelength Frame Multiplication on a Long Pulse Spallation

Source

Principle Proposed by F. Mezei and M. Russina, tested on the BNC TOF instrument by Gy. Káli.

GINA: Polarized Neutron Reflectometer

Thin layer investigations, including magnetic layers.

Superconductor-ferromagnet interface.


Concept of the polarizer filter

Picture of the setup in actual use on the GINA reflectometer

Technical data• Polarization efficiency: 99,3 %• Transmission: 74,5 %

Advantages • Extremely high polarization efficiency• Maintenance-free • Optical axis conserved

Disadvantage• Relatively low transmission

New four-bounce polarizer and analyzer filters have been installed

Motivation:• To study solid-liquid interfaces• Controlled temperature• Controlled liquid composition for contrast enhancement

The existing setup

Current status:• Being tested

• Background measurements • Heat stability• Contrast matching Si-wafer


New sample environment cell has been developed

SANS: Small Angle Scattering Spectrometer

The SANS diffractometer Yellow Submarine covers a Q-range from 0.003 to 0.7 Å-1 allowing to probe structures at length scales from 5 Å to 1500 Å. It has a wide range of applications from studies of defects and precipitates in materials, surfactant and colloid solutions, ferromagnetics, magnetic correlations, alloy segregation, polymers, proteins, biological membranes.


Effect of illumination on the two-dimensional SANS profile of magnetically oriented spinach thylakoid membranes, recorded with the 2D detector of the D22 SANS instrument (ILL). Dark-adapted state (A), after illumination with white light of 1700 μmol photons m-2 s-1 photon flux density for 5 min (B), after 5 min light and 5 min dark (C).

On isolated plant thylakoid membranes we could identify a peak originating from domains of ordered, unappressed stroma lamellae (a part of the highly organized thylakoid membrane assembly), providing information about its averaged repeat distance (RD) values. We found this RD to depend on e.g. the osmolarity and the ionic strength of the suspension medium. We also determined characteristic RDs of thylakoid membranes in algal or cyanobacterial cells and correlated these RDs with the size and the arrangement of the different protein complexes in the thylakoid membranes. Time-resolved SANS measurements were performed on these samples and revealed light-induced reversible reorganizations in the seconds-to-minutes time scale, which appeared to be associated with functional changes in vivo.


SANS analysis of steel samples (a) S1 as received, (b) S2 aged at low temperature, (c) S3 aged at high temperature. This yields the characteristic effect of the thermal treatment and helps evaluate the aging process.

SANS investigation of a duplex steel (containing two different phases) of industrial interest subjected to various ageing processes. We have observed the growth of cuboid particles with size changes from a ≈ 17 nm to a≈ 20.5 ± 6.6 nm due to thermal treatment. Further thermal treatment causes a developing of polydispersity of scattering particles. Therefore in this case only an average size was estimated. It was shown that this system becomes very polydisperse and the scattering data can be approximated by average parameter of particles as a ≈ 17 nm.


Original PublicationÜnnep R, Zsiros O, Solymosi K, Kovács L, Lambrev PH, Tóth T, Schweins R, Posselt D, Székely NK, Rosta L, Nagy G, Garab G. (2014) The ultrastructure and flexibility of thylakoid membranes in leaves and isolated chloroplasts as revealed by small-angle neutron scattering. Biochim Biophys Acta, 1837(9):1572-80.

FSANShigh resolution extension of the BNC Yellow Submarine SANS instrument

Single beam pinhole collimator• transfer parameter: A 1.5105 cm2sr; • angular resolution: 1.9 mrad; • optimal wavelength resolution: 12%;• sample size: 10 mm.

Multibeam converging collimator• transfer parameter: nA 3.8105 cm2sr;• angular resolution: 0.56 mrad;• optimal wavelength resolution: 3.6%;• sample size: 28 mm.

Elliptical focusing• transfer parameter: A 2.3105 cm2sr• angular resolution: 0.9 mrad;• optimal wavelength resolution: 6%;• sample size: 60 mm.

FSANS

First beam test results

Elliptical reflective focusingNested Kirkpatrick-Baez mirror pair

FSANS Test bench for optical developments

ATHOS: Cold Neutron Three-Axis Spectrometer

A triple-axis spectrometer has been designed for structural and dynamical studies of condensed matter. It is used in a multi-purpose regime: high resolution diffractometry, strain analysis, quasielasctic and inelastic scattering.

TAST: Thermal Neutron Three-Axis Spectrometer

The TAST instrument provides moderate resolution (~2.0 meV) with sufficient intensity for use in a wide range of problems. It is ideally suited for the study of phonon and magnon dispersion curves in single crystals, phonon density of states for large class of materials which contain hydrogen. The flexibility of the triple axis spectrometer enables to use it in a multi-purpose regime e.g. transmission measurements and spectrometer components tests are done also.

TAST: Thermal Neutron Three-Axis Spectrometer

3D reconstruction of nuclei positions around H in PdH.

Atomic resolution neutron holography

- internal source method (ammonium-chloride)- internal detector (converter) method (lead-cadmium alloy)

- neutron holography of policrystalline samples- holographic reconstruction of magnetic fields at atomic level

REF: Reflectometer

New monochromators have been installed and tested – now in regular operation

-PG with 0.4º mosaicity instead of 3º

Special alignment of crystal elements for optimal neutron transportation and focusing to the sample centre

-horizontal neutron SMs between slits on top and bottom

Monte-Carlo simulations (VITESS):

14 times increased intensity

REF: Reflectometer

Monochromator alignment

- optical alignment (using laser beam and a screen) of individual crystals (slightly diffuse reflection from PG surface)

- crystal positions adjusted in neutron beam

The measured yield of individual crystals of the outer monochromator.

Symmetrical intensity distribution.

neutron scattering at the budapest neutron centre

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