cryogenie

Cryogenie, or cryogenics in English, is the branch of physics and engineering that studies and applies very low temperatures, typically below −150 °C (123 K). It covers methods for producing such temperatures, the behavior of materials and fluids at low temperatures, and the design of insulated systems and containers for handling cryogenic fluids. The field enables the liquefaction of gases, the study of quantum and superconducting phenomena, and a range of practical technologies.

History and principles: Early achievements include the liquefaction of air and helium by Heike Kamerlingh Onnes in the early 20th century, leading to the discovery of superconductivity in 1911 at very low temperatures. Cryogenics relies on thermodynamic cycles and cryogenic fluids, such as liquid nitrogen, helium, and hydrogen, and uses insulation and vacuum techniques to minimize heat gain.

Applications: Cryogenics supports cryopreservation of biological material (sperm, embryos, tissues), cryosurgery, and food freezing. It plays a crucial role in space technology and propulsion, in superconducting magnets for MRI and in particle detectors, and in various scientific experiments that require liquefied gases or ultra-low temperatures (for example, detectors and dilution refrigerators).

Equipment and safety: Common equipment includes dewars, cryostats, transfer lines, and vacuum-insulated vessels. Working with cryogens requires protective gear and adequate ventilation; liquids like nitrogen and helium can cause cold burns and pose an oxygen deficiency risk. Materials may become brittle at low temperatures, and proper handling, monitoring, and training are essential.

Terminology: Cryogenics is sometimes distinguished from cryonics, which refers to the speculative future preservation of humans after death by freezing. Cryogenics is established science and engineering, whereas cryonics remains controversial.