Abstract: A gas transfer hose for connecting a cryogenic apparatus to a superconducting system such as a magnetic resonant imaging system. The improved gas transfer hose, in operation, is quieter than hitherto.

Abstract: A cryostat cooled by a pulse tube refrigerator and containing electrically powered equipment, wherein an electrical conductor is provided to the electrically powered equipment, said electrical conductor being in thermal and mechanical contact with one or more of the tubes of the pulse tube refrigerator.

Abstract: A pulse tube refrigerator system comprises a pulse tube refrigerator and a compressor coupled together via a high pressure line and a low pressure line. Cryogenic fluid is transferred to the PTR via the high pressure line and returned to the compressor via the low pressure line. The system further comprises an acoustic tuning device coupled to the low pressure line between a low pressure output from the PTr and a lower pressure input to the compressor, such that noise and vibration in the PTR system are reduced.

Abstract: A pulse tube refrigerator comprises a fixed pressure casing (3) containing cold parts and a removable pressure casing (2) containing serviceable parts. The fixed pressure casing (3) and the removable pressure casing (2) are coupled together via a joining member (1). During cooling operation the joining member (1) is arranged such that refrigerant fluid flows between the fixed and the removable casings. During servicing the joining member is arranged to cut off flow of refrigerant fluid between the fixed and removable casings, such that refrigerant in the fixed casing is trapped and parts in the removable casing are accessible for servicing. After servicing, substantially pure refrigerant fluid is pumped into the removable casing (2), the fixed and removable casings are re-joined and the joining member (1) is arranged such that refrigerant fluid flows between the casings again.

Abstract: A pulse tube refrigerator system comprises a pulse tube refrigerator (1) and a compressor (2) coupled together via a high pressure line (3) and a low pressure line (5), wherein cryogenic fluid is transferred to the PTR via the high pressure line and returned to the compressor via the low pressure line. The system further comprises an acoustic tuning device (7, 9) coupled to the low pressure line between a low pressure output (8) from the PTR and a low pressure input to the compressor, such that noise and vibration in the PTR system are reduced.

Abstract: A pulse tube refrigerator comprises a fixed pressure casing (3) containing cold parts and a removable pressure casing (2) containing serviceable parts. The fixed pressure casing (3) and the removable pressure casing (2) are coupled together via a joining member (1). During cooling operation the joining member (1) is arranged such that refrigerant fluid flows between the fixed and the removable casings. During servicing the joining member is arranged to cut off flow of refrigerant fluid between the fixed and removable casings, such that refrigerant in the fixed casing is trapped and parts in the removable casing are accessible for servicing. After servicing, substantially pure refrigerant fluid is pumped into the removable casing (2), the fixed and removable casings are re-joined and the joining member (1) is arranged such that refrigerant fluid flows between the casings again.