Cryogenics technically means a few degrees away from absolute zero degrees which is 0K on the Kelvin scale and as −273.15°C on the Celsius scale and as −459.67°F on the Fahrenheit scale. This is a theoretical value that in practice is not reached. Liquid Nitrogen which is used in Cryogenics exists between the temperatures of 63 K and 77.2 K
(-346°F and -320.44°F). Below 63 K, nitrogen freezes and becomes a solid. Above 77.2 K, nitrogen boils and becomes a gas. Since when liquid nitrogen is used in laboratories and in cryogenics it is in a boiling liquid state, it shows a temperature of 77.2 K. This is approximately -320 degrees Fahrenheit and -195.555556 degrees Celsius.
In practice, specimens may be submerged or held in the cryogenic vapor. In testing of our CryoTek material, vials were tested both ways and when frozen and thawed. Labels held throughout. See my earlier Blog post for more specifics on the testing that was done.