Recondensing service neck for cryostat

A service neck and refrigerator assembly for a cryostat, comprising:

• a service neck tube for providing access to the interior of the cryostat;
• a recondensing surface for recondensing liquid cryogen boiled off from a liquid cryogen within a cryostat;
• a refrigerator for cooling the recondensing surface to below the boiling point of the cryogen;
• and
• a thermal link provided between a cooling surface of the refrigerator and a part of the service neck tube;
• wherein
• an interior surface within said part of the service neck tube forms the recondensing surface;
• and
• a surface of the thermal link is exposed within the service neck tube, said exposed surface being the interior surface that forms recondensing surface.