| 摘要 |
A cryostat enclosing an actively-shielded superconducting magnet, itself comprising inner coils 11 and outer coils 10 within a cryogen vessel 12. A receptacle 40 is provided within the cryogen vessel, arranged such that, in use, the receptacle 40 contains liquid cryogen to a first level to partially immerse the inner coils 11 while the cryogen vessel contains liquid cryogen to a second level, lower than the first level, to partially immerse the outer coils 10. The receptacle is arranged such that over filling will cause the cryogen to overflow into the cryogen vessel. The cryostat preferably includes a recondensing refrigerator 17 arranged to condense vapour from the cryogen vessel into liquid cryogen and direct it to the receptacle. |
