Cryogenics

Cryogénie (Fr). Kryotechnik (Ge). Criogenia (It). Criogenia (Sp). Криогеника (Ru).

The field of cryogenics studies the regularities of properties alternation of various substances under conditions of extremely low (“cryogenic”) temperatures; involves technologies and hardware-methodical means of work at low temperatures. Temperatures below -180°C (93 K; −292 °F) are considered as cryogenic. [1]

Liquefied gases, such as liquid nitrogen and liquid helium, are used in many cryogenic applications. Liquid nitrogen is the most commonly used element in cryogenics and is legally purchasable around the world. Liquid helium is also commonly used and allows for the lowest attainable temperatures to be reached.[2]

Liquid nitrogen is used as part of the cooling system in X-ray diffractometers and (S)TEMs. In the case of EM cooling down organic samples allows them to be irradiated with electrons to minimize the radiation damage effects. It also helps conserve the crystallinity under vacuum for those samples capable of losing solvates.

For a dedicated electron diffractometer, this feature would of great importance, since the beam temperature can cause damage to the samples utilized for diffraction. Using a dedicated electron diffractometer with cryogenic capabilities would ensure that the samples remain intact.

References:

1 R. E. Bilstein, “Stages to Saturn. A Technological History of the Apollo/Saturn Launch Vehicle”, NASA History Office, Washington, DC 1996, 89-91.

2 “Cryogenics”, accessed on September 21, 2020, https://en.wikipedia.org/wiki/Cryogenics.