I have a few questions. LN2 costs are only a couple of percent of Alcor's operating expenses. They are, however, almost half of the patient care expenses.
Patient care is extremely well funded.
Nevertheless, any improvements we can make in this area will improve security even further and help hold down funding minimums for new members coming in. So as you can see, Alcor's dewars are pretty efficient. Not until the mean free path of the gas molecules becomes comparable to the wall separation does the conductivity suddenly drop. In fact, the vacuum is so high that even trace amounts of helium in the atmosphere can diffuse through the steel walls and ruin the vacuum enough to increase the LN2 boiloff rate. Superinsulation consists of multiple layers of reflective metal foil that reduces radiative heat transfer to near zero.