Technology and Applications of the High‑Pressure Neutron Diffractometer at China Spallation Neutron Source

The High-Pressure Neutron Diffractometer (HPND) at China Spallation Neutron Source (CSNS) is the first time-of-flight neutron diffractometer in China dedicated to material structure research under high pressure. The HPND is a neutron instrument that combines both diffraction and imaging capabilities. It employs a decoupled water moderator, delivering a neutron flux greater than 10⁷ n/cm²/s in both experiment hutches at 160 kW power, with a 90° detector resolution better than 0.6 %. The HPND is equipped with two experiment hutches and can be coupled with various extreme sample environments, such as high pressure, high temperature, low temperature and high magnetic fields, to enable structural measurements of materials under extreme conditions. Currently, the HPND is equipped with an automatic sample exchange device, a cryostat device, a piston‑cylinder cell (Clamp Cell), and a Paris-Edinburgh press (VX4), allowing in‑situ neutron diffraction experiments at temperatures down to 1.5 K and pressures exceeding 15 GPa. The HPND is scheduled to officially open to users in October 2026, will become a key tool for investigating structural evolution of materials under extreme conditions.