Journal of large-scale research facilities, 1, A28 (2015) http://dx.doi.org/10.17815/jlsrf-1-26 Published: 19.08.2015 KWS-1: Small-angle scattering di�ractometer Heinz Maier-Leibnitz Zentrum Forschungszentrum Jülich, Jülich Centre for Neutron Science Instrument Scientists: - Henrich Frielinghaus, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Garching, Germany, phone: +49(0) 89 289 10706, email: h.frielinghaus@fz-juelich.de - Artem Feoktystov, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Garching, Germany, phone: +49(0) 89 289 10746, email: a.feoktystov@fz-juelich.de - Ida Berts, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Garching, Germany, phone: +49(0) 89 289 10758, email: i.berts@fz-juelich.de - Gaetano Mangiapia, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Garching, Germany, phone: +49(0) 89 289 54810, email: g.mangiapia@fz-juelich.de Abstract: The KWS-1, which is operated by JCNS, Forschungszentrum Jülich, is a small-angle neutron scattering di�ractometer dedicated to high resolution measurements. 1 Introduction KWS-1 is dedicated to high resolution measurements (Feoktystov et al., 2015) due to its 10 % wavelength selector. This property is interesting for highly ordered or highly monodisperse samples. With the fore- seen chopper the wavelength uncertainty can be reduced further to ca. 1 %. The scienti�c background of KWS-1 is placed in magnetic thin �lms. Magnetic samples will be studied with the full polarisation analysis including incident beam polarisation and polarisation analysis of the scattered neutrons. In front of the collimation, a 3-cavity polariser with V-shaped mirrors is placed. The full bandwidth of 4.5 to 20 Å will be covered with min. 90 % (95 % typical) polarisation. A radio frequency spin �ipper allows for changing the polarisation. The polarisation analysis will be realised with 3He-cells which will be optimised for the used wavelength and scattering angle. Vertical magnets will be provided to render the magnetic �eld at the sample position. Thin �lms can be well studied in the grazing incidence geometry – the method is called grazing incidence small angle neutron scattering (GISANS). A newly installed hexapod will allow for positioning the sample with 0.01 mm and 0.01° precision. 1 http://jlsrf.org/ http://dx.doi.org/10.17815/jlsrf-1-26 https://creativecommons.org/licenses/by/4.0/ Journal of large-scale research facilities, 1, A28 (2015) http://dx.doi.org/10.17815/jlsrf-1-26 Figure 1: Instrument KWS-1 (Copyright by W. Schürmann, TUM). Classical soft-matter systems will be investigated on KWS-1 if the resolution is needed. Biological samples can be handled due to the detector distance of ca. 1 m, which will allow for maximal scattering angles of Q = 0.5 Å-1. The MgF2 lenses are used for the high �ux mode with large sample areas, while the resolution stays in the classical SANS range. These enhanced intensities allow for real time measurements in the 1/10 second region (typical 1 s). The chopper in parallel allows for studying faster dynamics in the ms range. The so-called TISANE mode interlocks the chopper frequency with the excitation �eld frequency and with the detection bin- ning. The precise consideration of the �ight times allows for higher precision compared to classical stroboscopic illuminations. 2 Typical Applications • Grain boundaries • Alloys • Magnetic structures • Flow lines • Soft matter and biology (as for KWS-2) • Complex �uids near surfaces • Polymer �lms • Magnetic �lms • Nanostructured �lms 3 Sample Environment • Rheometer shear sandwich • Rheowis-�uid rheometer (max. shear rate 10000 s-1) • Anton-Paar �uid rheometer • Stopped �ow cell 2 http://dx.doi.org/10.17815/jlsrf-1-26 https://creativecommons.org/licenses/by/4.0/ http://dx.doi.org/10.17815/jlsrf-1-26 Journal of large-scale research facilities, 1, A28 (2015) Figure 2: Schematic drawing of KWS-1. • Sample holders: 9 horizontal x 3 vertical (temperature controlled) for standard Hellma cells 404-QX and 110-QX • Oil & water thermostats (range -40 °C – 250 °C), electric thermostat (RT – 200 °C) • 8-positions thermostated (Peltier) sample holder (-40 °C – 150 °C) • Magnet (horizontal, vertical) • Cryostat with sapphire windows • High temperature furnace • Pressure cells (500 bar, 2000 bar, 5000 bar) 4 Technical Data 4.1 Overall performance • Q = 0.0007 – 0.5 Å-1 • Maximal �ux: 1.5 · 108 n cm-2 s-1 • Typical �ux: 8 · 106 n cm-2 s-1 (collimation 8 m, aperture 30 x 30 mm2, λ = 7 Å) 4.2 Velocity selector • Dornier, FWHM 10 %, λ = 4.5 Å – 12 Å, 20 Å 4.3 Chopper • For TOF-wavelength analysis, FWHM 1 % 4.4 Polariser • Cavity with V-shaped supermirror, all wavelengths • Polarisation better 90 %, typical 95 % 4.5 Spin-�ipper • Radio-Frequency spin �ip probability better than 99.8 % 3 http://dx.doi.org/10.17815/jlsrf-1-26 https://creativecommons.org/licenses/by/4.0/ Journal of large-scale research facilities, 1, A28 (2015) http://dx.doi.org/10.17815/jlsrf-1-26 4.6 Active apertures • 2 m, 4 m, 8 m, 14 m, 20 m 4.7 Aperture sizes • Rectangular 1 x 1 mm2 – 50 x 50 mm2 4.8 Sample aperture • Rectangular 1 x 1 mm2 – 50 x 50 mm2 4.9 Neutron lenses • MgF2, diameter 50 mm, curvature 20 mm • Packs with 4, 6, 16 lenses 4.10 Sample stage • Hexapod, resolution better than 0.01°, 0.01 mm 4.11 Detector 1 • Detection range: continuous 1.5 m – 20 m • 6Li-Scintillator 1 mm thickness + photomultiplier • E�ciency better than 95 % • Spatial resolution 5.3 x 5.3 mm2, • 128 x 128 channels • Max. countrate 0.6 MHz (τ dead = 0.64 µs) References Feoktystov, A. V., Frielinghaus, H., Di, Z., Jaksch, S., Pipich, V., Appavou, M.-S., . . . Brückel, T. (2015). KWS-1 high-resolution small-angle neutron scattering instrument at JCNS: current state. Journal of Applied Crystallography, 48(1), 61-70. http://dx.doi.org/10.1107/S1600576714025977 4 http://dx.doi.org/10.17815/jlsrf-1-26 http://dx.doi.org/10.1107/S1600576714025977 https://creativecommons.org/licenses/by/4.0/ Introduction Typical Applications Sample Environment Technical Data Overall performance Velocity selector Chopper Polariser Spin-flipper Active apertures Aperture sizes Sample aperture Neutron lenses Sample stage Detector 1