<i>In situ</i> small-angle X-ray scattering measurement at the Very Small Angle Neutron Scattering Instrument at the China Spallation Neutron Source

Small-angle X-ray and neutron scattering (SAXS and SANS) offer complementary insights into multi-scale and multiphase structures. Efforts have been made to integrate SAXS into SANS instruments, with only D22 at the Institut Laue-Langevin successfully implementing a SAXS setup; this was constrained to a horizontal geometry due to space limitations and high radiation noise. Here, we introduce an <i>in situ</i> vertical SAXS setup at beamline 14, Very Small Angle Neutron Scattering (VSANS) instrument, at the China Spallation Neutron Source. The compact vertical SAXS instrument without a beam stop, measuring 87 cm × 93 cm × 240 cm (W × L × H) and featuring a hoisting frame, can be easily installed in the VSANS sample room within 5 h. Utilizing a 50 mm-diameter neutron collimation guide, we can simultaneously detect X-rays from below and neutrons from behind, with the backboard of the SAXS chamber coated in a boron-aluminium alloy to reduce neutron background interference. Through testing with standard samples like deuterated and hydrogenated PEG, silver behenate, LaB₆, and glass carbon, we demonstrate that concurrent neutron and X-ray measurements are successful.