An upgrade beamline for combined wide, small and ultra small-angle x-ray scattering at the ESRF

This contribution presents the main design features of the upgraded beamline ID02 (TRUSAXS). The beamline combines different small-angle X-ray scattering techniques in one unique instrument. The key component of this instrument is an evacuated (5×10⁻³ mbar) stainless steel detector tube of length 34 m and diameter 2 m. Three different detectors (Rayonix MX170, Pilatus 300 K and FReLoN 4M) are housed inside a motorized wagon which travels along a rail system with very low parasitic lateral movements (± 0.3 mm). This system allows automatically changing the sample-to-detector distance from about 1 m to 31 m and selecting the desired detector. In addition, a wide angle detector (Rayonix LX170) is installed just above the entrance cone of the tube for optional wide-angle X-ray scattering measurements. The beamstop system enables monitoring of the X-ray beam intensity in addition to blocking the primary beam, and automated insertion of selected masks behind the primary beamstop. The focusing optics and collimation system permit to cover a scattering vector (q) range of 0.002 nm⁻¹ ≤ q ≤ 50 nm⁻¹ with one unique setting using 0.1 nm X-ray wavelength for moderate flux (5×10¹² photons/sec). However, for higher flux (6x10¹³ photons/sec) or higher resolution (minimum q < 0.001 nm⁻¹), focusing and collimation, respectively need to be varied. For a sample-to-detector distance of 31 m and 0.1 nm wavelength, two dimensional ultra small-angle X-ray scattering patterns can be recorded down to q≈0.001 nm⁻¹ with far superior quality as compared to one dimensional profiles obtained with a Bonse-Hart instrument.