The time-focusing neutron spectrometer SHARP

SHARP (Spectromètre Hybride Alpes Région Parisienne) is a new-generation time-of-flight neutron spectrometer installed at the Institut Laue-Langevin (ILL). It is designed to investigate dynamical processes in condensed matter with high energy resolution and broad experimental versatility. Developed as a complete upgrade of the former IN6 instrument, SHARP addresses key scientific challenges in soft matter, biology, energy materials, and solid-state physics, where precise measurements of atomic and molecular motions are essential.The main design objective is to achieve a higher counting rate while maintaining the IN6 strong neutron flux, by providing wide angular and energy coverage through multiple take-off angle geometries. Notable features include a fully vacuum-compatible secondary spectrometer, a retractable sample window allowing the detector tank to remain under vacuum while enabling experiments requiring controlled sample environments, and a bank of 240 position-sensitive 3 He detectors operating at 5 bar, ensuring enhanced spectral spatial definition. Compared to IN6, SHARP delivers a twofold increase in counting rate in the elastic region and a lower background. This paper outlines the scientific motivations behind the SHARP project, describes the main instrumental innovations, and demonstrates the instrument’s performance through initial scientific results on molecular diffusion in zeolite, determinant of the selectivity of these materials for use in membrane-based gas separations.