As disclosed herein, cryoprobes comprising no return line can be operated efficiently and safely on known supply systems for cryoprobes. Typically the supply systems provide a fluid for connected cryoprobes so that they will provide the desired cooling capacity. The cooling capacity can be adjusted through the supply system. An adapter for connecting a supply system with a cryoprobe for open fluid cooling, wherein the adapter comprises: a first fluid adapter connector for connecting a first supply terminal of the supply system; a second fluid adapter connector for connecting a second supply terminal of the supply system; a feed line output for connecting a feed line of the cryoprobe; a first fluid line for the fluid connection of the first fluid adapter connector with the feed line output; and a second fluid line for the fluid connection of the feed line output with the second fluid adapter connector, wherein the fluid flow in the second fluid line is reduced compared the one in the first fluid line.