Design and validation of a heated shear cell for in situ x-ray scattering under controlled temperature and deformation.

We report the design and validation of a compact heated shear cell for in situ structural characterization of materials under combined temperature and deformation control. The instrument applies prescribed linear reciprocating displacement to a parallel-plate geometry using programmable logic controller-based open-loop control, enabling reproducible shear deformation across experimentally relevant temperatures, amplitudes, and cycle frequencies. Emphasis is placed on quantitative validation of instrument performance, including measurements of temperature accuracy, temporal stability, plate-to-plate uniformity, and displacement repeatability during continuous shear at elevated temperatures. Independent temperature control of the stationary and moving plates ensures uniform thermal conditions at the sample, while the mechanical architecture accommodates large displacement amplitudes without introducing rotational or parasitic motion. An open Kapton window provides unobstructed access to the sample region, allowing simultaneous shear, heating, and real-time x-ray scattering measurements. The validated performance demonstrates reliable and stable operation under conditions relevant to soft matter and polymer processing studies. Representative in situ small-angle x-ray scattering measurements acquired at a synchrotron beamline further confirm stable, low-background data acquisition under coupled thermomechanical conditions, validating the instrument for its intended application. The modular design and straightforward control architecture establish the shear cell as a robust and adaptable platform for coupled mechanical deformation and in situ structural measurements.