Sometimes, a dewar arrives warm and without any visible or noticeable breaks in any of the common breakpoints, such as the neck. In these situations, it is possible that the vacuum has been lost on the dewar over time, preventing it from holding temperature. NE-CAT can check the integrity of the vacuum by pumping down the dewar, then, while the dewar is under vacuum, Ed Lynch flows helium gas over the outside of the vacuum vessel, especially at the seams. If the vacuum is not intact, the helium will be sucked inside and the pump system has a residual gas analyzer which can detect if helium is entering the system. If the vacuum is maintained, NE-CAT will charge the dewar with LN2 to determine if it is functional and make sure that the leak does not occur only when the dewar is cold. Afterwards, we send it back to the user with their samples.
Our dewar recovery service can save users the substantial cost of a new dewar and we will perform it on any dewar that arrives intact and warm.