Sprecher
Beschreibung
The small-angle neutron scattering (SANS) diffractometer KWS-2 [1-4] is dedicated to the investigation of multi-scale morphologies in soft condensed matter and biophysical systems, bridging atomic- and meso-scale structures. By combining pinhole SANS (8 mm spatial resolution) with a focusing mode using MgF₂ lenses and a secondary high-resolution detector (1 mm spatial resolution), as well as wide-angle neutron scattering (WANS) detection (a third detector covering scattering angles up to s ≃ 50°), the instrument provides access to a wide Q range, from 10⁻⁴ to 2.0 Å⁻¹ [5–7]. This can be achieved either with tunable resolution (Δλ/λ between 1% and 10%, adjusted using the time-of-flight (TOF) mode with the resolution chopper) [3, 8] or with enhanced intensity through the focusing mode, which employs a large beam size while maintaining the same Qmin resolution on the main SANS detector as in pinhole mode, yielding up to a tenfold increase in neutron intensity at the sample position [4]. In addition, a secondary background chopper, installed on demand upstream of the sample position, enables TOF measurements in the high-Q regime by separating inelastically scattered neutrons from hydrogenous samples, thereby suppressing the incoherent background [9].
Colloidal, gel, and micellar systems, as well as hierarchically organized semi-crystalline materials such as ion-exchange membranes or complexes formed by polymers in solution with other macromolecular species, particularly benefit from the versatility of the instrument's characterization modes [5–8, 10, 11].
The instrument also provides high-quality data for functionalized nanoparticles and small biological systems, enabling structural analyses with molecular-level discrimination between competing models [12, 13]. Examples of studies on systems relevant to soft matter, biophysics, and materials science, including the availability of in situ SEC, FTIR and UV–Vis spectroscopy at KWS-2, will be discussed [7, 14].
References
[1] A. Radulescu et al., J. Appl. Cryst. 48, 1860 (2015).
[2] J. Houston et al., J. Appl. Cryst. 51, 323 (2018).
[3] A. Radulescu, J. Appl. Cryst. 57, 1040 (2024).
[4] A. Radulescu et al., J. Appl. Cryst. 58, 1582 (2025).
[5] S. J. Talley et al., ACS Appl. Mater. Interfaces 11, 31508 (2019).
[6] B. Krugmann et al., Scientific Reports 10, 16691 (2020).
[7] F. Kaneko et al., Polymer 295, 126771 (2024).
[8] J. Puig-Rigall et al., J. Colloid Interf. Sci. 524, 42 (2018).
[9] L. Balacescu et al., J. Appl. Cryst. 54, 1217 (2021).
[10] M. M. Schiavone et al., J. Appl. Cryst. 56, 947 (2023).
[11] B. Joseph Boniface et al., J. Colloid Interf. Sci. (in press).
[12] Y. Wu et al., Nanoscale 17, 3798 (2025).
[13] X. Liu et al., Angew. Chem. Int. Ed. 64, e202516308 (2025).
[14] E. A. Kelley et al., Soft Matter 15, 1253 (2019).