Design and testing of high-temperature and high-pressure cell for SANS at CSNS.

With the stable operation of the Small-Angle Neutron Scattering (SANS) instrument at the China Spallation Neutron Source, the demand for diverse sample environments has significantly increased. Common atmospheric pressure conditions are no longer sufficient for user experiments, making it essential to develop new sample environment equipment that allows the samples to be tested under a joint high-temperature and high-pressure (HTHP) condition. In situ HTHP-SANS experiments are crucial for studying materials such as shale, gas hydrate, biological proteins, and colloids. The HTHP equipment developed in this study allows the simultaneous control of three critical environmental parameters: temperature, uniaxial pressure, and fluid pressure. This capability enables the comprehensive investigation of the structures and properties of various materials under multi-dimensional conditions. Test results indicate that the HTHP cell can safely operate under a sample pressure of 100 MPa and a temperature of 100 °C, accommodating the pressure and temperature control requirements needed by most SANS users with various research backgrounds in materials, energy, geological, and biological fields.