My experience with xtals frosting in LN2 either in a dewar, while freezing, or in pucks, has been because the LN2 was contaminated with ice crystals The fog you see above your dewar when freezing xtals is frozen water vapor...it will fall and collect in the LN2 and also deposit on the xtals. Dewars filled with recycled LN2 get contaminated with ice. Dewars dried upside down allow the cold gas to flow out and warm moist air to flow in and the water to condense inside the dewar (basic physics). To dry shipping dewars keep up right while warming. Steve
Sent from my iPad On Jul 11, 2013, at 5:25 PM, "Nathaniel Clark" <nathanielcl...@gmail.com<mailto:nathanielcl...@gmail.com>> wrote: At our last synchrotron trip, the beamline staff suggested that the problem was due to moisture accumulation in the dry shipper. They recommended storing them inverted (for a few weeks, if I recall), and/or putting a supply of dry air in the dewer. Haven't tried it yet! Nat On Thu, Jul 11, 2013 at 5:08 PM, <Rain Field> <rainfiel...@163.com<mailto:rainfiel...@163.com>> wrote: Hi All, We found if the crystals are storaged in pucks for 3-4 days in shipping dewar (with liquid nitrogen), they are almost frosted. Although I can wash them with liquid nitrogen, but it's not convenient to do that for each crystals. I doubt it's because the humid air in North West America. Does anyone has an idea how to avoid this? Thank you!
