Development of the sample environment system for the DN-12 diffractometer on the IBR-2M pulsed reactor (pressure – temperature – magnetic field). Project status

The neutron diffraction experiments with microsamples use specific sample environment systems. One of such systems is under development in this project for the DN-12 diffractometer on the IBR-2M reactor. It is needed to keep of the investigated sample in the next simultaneous conditions: a high-uniformity magnetic field up to 4T, high pressure and low temperatures down to 4 K.

The arrangement of detectors of the diffractometer restricts the operations of the magnet construction and the magnetic field uniformity. The developing magnet is a superconducting split-coil type magnet. This provides the neutron scattering perpendicularly towards the vector of the magnetic field and to the beamline, as well as the scattering directed forward under the angle of 45 degrees.

The HTSC (high-temperature superconductor) magnet is made of YBCO tape with a critical current in the range of 300A@77K. The cryocooler ("cryogen-free") has been used for cooling the magnet. The cryostat also holds coaxial cylindrical channel from stainless steel provided by its own vacuuming system with an internal diameter of 79 mm for the access of the sample into the existing high pressure cell, which is cooled by the second cryocooler. Both of the cryostats are in a horizontal lay-out.

This report focuses on the description of the system and the parameters obtained at the first experiment. (paper)