General Dewar requirements
The purpose of the Dewar vessel is to hold the liquid nitrogen supply used by the Cryostream.
Oxford Cryosystems recommend a stainless steel or aluminium Dewar with capacity between 30 and 60 litres.
As the Cryostream supply line is only 700 mm long, it can only utilise the top 650 mm of a Dewar vessel. Using a 100 litre Dewar may sound like a good idea, but if the rigid Supply Line does not reach the bottom, the Cryostream will not utilise its full capacity.
Dewar necks vary in size. If the opening is too small, there maybe problems refilling the Dewar. If the Dewar opening is too large, then the rate of boil off will be very high and contaminants will get into the liquid nitrogen. 5cm is the optimum neck size for the Cryostream.
ES60 Dewar Vessel
Oxford Cryosystems supply a specially made 60 litre stainless steel Dewar called the ES-60 with a neck opening size of 5cm. This Dewar is the optimum size to allow the Cryostream to run from Friday lunch time to Monday lunch time without needing to be refilled. For even longer run periods, try an Auto-Fill system.
