MLZ is a cooperation between:

Technische Universität München> Technische Universität MünchenHelmholtz-Zentrum Hereon> Helmholtz-Zentrum Hereon
Forschungszentrum Jülich> Forschungszentrum Jülich

MLZ is a member of:

LENS> LENSERF-AISBL> ERF-AISBL

MLZ on social media:

Logo

MLZ (eng)

Lichtenbergstr.1
85748 Garching

KWS-2

Small angle scattering diffractometer

This instrument is focussed on cold neutrons. All parameters given here are valid during the current operation of FRM II. Please get in touch with the instrument team well in advance for all further details (length of experiment etc.).

Insrumentscheme KWS-2 Insrumentscheme KWS-2

KWS-2 [1] is a classic small-angle scattering diffractometer at which a large Q range between 2.0 · 10-3 and 1.0 Å-1 can be examined using the pinhole camera principle with different neutron wavelengths and detection distances (gallery, fig. 1,2). The instrument is dedicated to the investigation of mesoscopic structures and structural changes due to the fast kinetic processes in the fields of soft matter, chemistry and biology [2]. The instrument resolution is set by the mechanical monochromator (velocity selector) to either Δλ/λ = 10 % (in the non-inclined configuration) or Δλ/λ = 20 % (in the inclined configuration) [3,4]. The resolution can further be set between 2 % and 10 % by using the main double-disk chopper with adjustable opening windows [5] (gallery, fig. 2, 3). The new large-area detection system with fast readout electronics [6] allows new ways of increasing performance, including high-intensity/ small background measurements (when using the secondary one-disk chopper) [7].

Finally, the ability to use the mechanical monochromator in an inclined position with respect to the beam axis (gallery, fig. 4) offers the availability of thermal neutrons (λ = 2.8 Å) at the instrument. The neutron flux at the sample position (gallery, fig. 5) varies with the wavelength and the wavelength resolution, i.e. with the setting of the velocity selector. (gallery, fig. 4-6)

[1] A. Radulescu et al., J. Phys. Conf. Series 351, 012026 (2012)
[2] A. Radulescu et al., J. Vis. Exp. 118, e54639 (2016), KWS-2 film
[3] A. Radulescu, Ioffe, A., Nucl. Inst. Meth. A, 586 , 55 (2008)
[4] A. Radulescu et al., Nucl. Inst. Meth. A 689, 1 (2012)
[5] A. Radulescu et al., J. Appl. Cryst. 48, 1860 (2015)
[6] J. Houston et al., J. Appl. Cryst. 51, 323 (2018)
[7] L. Balacescu et al., J. Appl. Cryst. 54, 1217 (2021)

Typical Applications
  • Colloids, nanocomposites, polymer gels, networks
  • Polymer blends, diblock copolymers
  • Microemulsions, complex fluids, micelles
  • Membranes, films; in-situ adsorption – desorption/ humidifying – drying phenomena
  • Shear induced micelle deformation, rubber network deformation, nanocomposite ordering
  • In-situ crystallisation semi-crystalline polymer
  • Nanoparticles for drug delivery and vaccines
Sample Environment
  • Anton-Paar fluid rheometer
  • Stopped flow device
  • Cuvettes holders: 9 horizontal x 3 vertical (temperature controlled) for standard Hellma Cuvettes 404.000-QX and 110-QX
  • Oil & water thermostats (typical 10 …100°C)
  • 8-positions and 2 × 6 positions thermostated (Peltier) sample holder (-40°C … 150°C)
  • Humidity chamber, 5 % … 95 % for 10°C … 60°C
  • Stretching apparatus (4 devices in a common set-up) for controlled stretching in beam
Complementary in-situ techniques (optional at sample aperture, see instrument drawing)
  • FT-IR spectroscopy
  • DLS & SLS
  • 3He spin analyser (SEOP)
  • SEC-SANS (soon)
Technical Data
Overall performance
  • Q = 0.002… 1 Å-1 (gallery, fig. 2)
  • Flux
    • 8 · 106 n cm-2 s-1 for λ= 2.88 Å
    • 1.9 · 107 n cm-2 s-1 for λ= 5.0 Å (gallery, fig. 5,6)
Velocity selector
  • Astrium, Δλ/λ = 20 % (tilted selector), λ = 2.8… 7 Å
  • Δλ/λ = 10 % on request (lower flux)
Resolution Chopper
  • Tunable Δλ/λ: 20 %… 2 % (TOF analysis) (gallery, fig. 3)
Active apertures
  • 2 m, 4 m, 8 m, 14 m, 20 m, sample position
Aperture sizes
  • Rectangular 1 × 1 mm2 – 50 × 50 mm2
Sample stage
  • XYZθ translational-rotational stage + cradle
  • Accuracy better than 0.01°, 0.01 mm
  • Robot with multiple positions cuvette carousel (soon)
Background chopper
  • 1-disc with 4 opening windows (1 cm x 1 cm), frequency 10 – 45 Hz
  • TOF data acquisition in the high-Q regime (1 – 4 m detection distance)
  • separation of the inelastic and elastic scattering from the hydrocarbon systems
Detector
  • Detection range: continuous 1 – 20 m
  • 3He tubes array
  • active area ~0.9 m2
  • count rate for no deadtime > 2 MHz
  • resolution = < 8 mm
  • efficiency 88 % for 5 Å, 75 % for 2.8 Å
  • semi-transparent beamstop, simultaneous measurement of transmission and scattering

Instrument Scientists

Dr. Aurel Radulescu
Phone: +49 (0)89 158860-712
E-Mail: a.radulescu@fz-juelich.de

Dr. Jia-Jhen Kang
Phone: +49 (0)89 158860-739
E-Mail: j.kang@fz-juelich.de

Dr. Marie-Sousai Appavou
Phone: +49 (0)89 158860-747
E-Mail: m.s.appavou@fz-juelich.de

KWS-2
Phone: +49 (0)89 158860-510

Operated by

JCNS

News

ERuM Pro Project NHSM

ERuM Pro Project NHSM

Read more
Helping hands for the future

Helping hands for the future

Read more

Film: Roboter changes samples

Roboter for samples at KWS-2
Roboter for samples at KWS-2 Fully automated: A roboter changes the samples at the instrument KWS-2 © Alexander Weber / JCNS
Fully automated: A roboter changes the samples at the instrument KWS-2 © Alexander Weber / JCNS

Publications

Find the latest publications regarding KWS-2 in our publication database iMPULSE:

impulse.mlz-garching.de

Citation of the instrument

Heinz Maier-Leibnitz Zentrum. (2015). KWS-2: Small angle scattering diffractometer. Journal of large-scale research facilities, 1, A29. http://dx.doi.org/10.17815/jlsrf-1-27

For citation please always include the DOI.

Gallery

KWS-2 - Figure 1
KWS-2 - Figure 1

KWS-2 Layout

© Forschungszentrum Jülich GmbH
KWS-2 - Figure 2
KWS-2 - Figure 2

The Q-range covered at KWS-2 with different neutron wavelengths.

KWS-2 - Figure 3
KWS-2 - Figure 3

The instrument resolution at KWS-2.

KWS-2 - Figure 4
KWS-2 - Figure 4

Calibration of the mechanical monochromator (velocity selector) of KWS-2.

Flux-distribution-KWS2
Flux-distribution-KWS2

The simulated flux distribution (Mc-Stas) at different positions along the instrument guide system (vertically “S”-shaped) and at the sample position for different configurations of the velocity selector.

KWS-2 - Figure 6
KWS-2 - Figure 6

The simulated flux (Mc-Stas) at the sample position and different configurations of the velocity selector.

MLZ is a cooperation between:

Technische Universität München> Technische Universität MünchenHelmholtz-Zentrum Hereon> Helmholtz-Zentrum Hereon
Forschungszentrum Jülich> Forschungszentrum Jülich

MLZ is a member of:

LENS> LENSERF-AISBL> ERF-AISBL

MLZ on social media: