Kriogeenias

Kriogeenias, or cryogenics, is the branch of physics and engineering focused on production, storage, and use of materials at extremely low temperatures. It covers the liquefaction of gases, the behavior of matter near cryogenic temperatures, and the design of equipment to reach and maintain such conditions, typically below about −150 degrees Celsius (123 kelvin).

Historically, cryogenics emerged in the 19th and early 20th centuries with advances in low-temperature physics. Notable milestones include the liquefaction of air by Carl von Linde in 1877, the invention of the robust cryogenic Dewar vessel, and Heike Kamerlingh Onnes’s liquefaction of helium and discovery of superconductivity in 1908. Since then the field has expanded into industrial gas processing, medical applications, and fundamental research.

Core principles involve thermodynamics, heat transfer, and phase transitions at low temperatures. Techniques include refrigeration cycles using various working substances, Joule-Thomson expansion, and vacuum insulation. Reaching millikelvin temperatures relies on dilution refrigerators and adiabatic demagnetization, while cryostats, Dewars, and cryogenic transfer lines enable practical experiments and operations.

Applications span scientific instrumentation, healthcare, and industry. They include superconducting magnets for MRI and particle accelerators, space vehicle propellants and cooling systems, ultra-low-temperature physics research, cryopreservation of biological samples, and industrial processing with liquid nitrogen or argon. Safety and cost considerations emphasize adequate ventilation to avoid oxygen deficiency, proper handling of cryogenic fluids to prevent cold burns, and robust containment to prevent pressure hazards.

Today kriogeenias continues to drive advances in materials science, quantum computing, and space technology, balancing technical challenges with the demand for reliable, efficient, and safe ultra-low-temperature operations.