Cryo-transfer revised

Vapour deposition of water is a major problem in cryo-transfer and cryo-observation of frozen specimens. The use of (sliding) shields to protect the specimen during transfer has been evaluated and was found to be a fail-safe procedure. Shielding the specimen with solidified coolant is proposed as an alternative or additional protection. The protective layer (ethane, Freon 22) can be evaporated in the high vacuum of the microscope. The evaporating coolant will carry away water films deposited on top. The temperature of coolant evaporation is low enough to prevent possible devitrification of water in the specimen itself.