Owing to their high penetrability and sensitivity to magnetism, neutrons are a fundamental probe for studying magnetism in various environments. Advanced magnetic materials often require special sample environments, such as low temperatures and high magnetic fields, to exhibit their intriguing functionality. Traditionally, cryostats and magnets require liquid-He as a cryogen for operations. However, the problems of considerable price increases and an unstable supply of liquid-He have risen recently. Additionally, handling liquid-He requires specialized knowledge and experience, necessitating dedicated human resources. Furthermore, experiments must be periodically interrupted for refills, resulting in substantial beam time loss.
 As part of our initiative toward restart of JRR-3 after a long shutdown, we introduced an advanced sample environment, a liquid-He-free magnet, and cryostat systems. We successfully realized a maximum magnetic field of 10 T and a low temperature of 1.5 K without using any liquid cryogen (Fig. 1 a). Additionally, we introduced three cryogen-free cryostats that share a common design for the sample space, allowing the shared use of sample sticks and ³He inserts (Fig. 1 b–d). This enabled us to reach temperatures as low as 0.3 K. Thus, the sample environment offered by this newly developed system facilitates safe, simple, and stable experiments under extreme conditions of 10 T and 0.3 K─this has become a key advantage of the restarted JRR-3 reactor.

This work was carried out through close collaboration within the framework of the international Society for Sample Environment and the manufacturer.