Cryogenic cooling

Cryogenic cooling lowers equipment to cryogenic temperatures, typically below about 120 kelvins, to reduce thermal motion and enable specialized physical measurements and technologies.

Thermal noise: Random fluctuations in a system caused by its finite temperature. Lower temperatures reduce this noise in sensors and measurement circuits.
Superconducting quantum interference device: A highly sensitive magnetometer that uses superconducting loops and Josephson junctions. Cooling enables superconductivity and improves the detection of tiny magnetic fields.
Kelvin: The SI unit of thermodynamic temperature, with zero at absolute zero. Cryogenic operating points are specified in kelvins, often far below 1 K.
Cryogen-free refrigeration: Cryogenic cooling produced by a refrigerator rather than by replenished liquid cryogens. It avoids routine cryogen refills but can introduce mechanical vibration.
Superconductivity: A state of matter with zero electrical resistance and expulsion of magnetic fields below a critical temperature. Cooling below a material's critical temperature enables superconducting magnets and circuits.
Cryocooler: A mechanical refrigerator designed to produce and maintain cryogenic temperatures. Closed-cycle cryocoolers remove heat without routinely consuming stored cryogens.
Transition-edge sensor: A calorimetric detector operated at the sharp superconducting transition between resistance and zero resistance. Its low-temperature operation lets tiny energy deposits produce measurable resistance changes.
Absolute zero: The limiting temperature at which a system has its minimum possible thermal energy. Cryogenic systems approach this limit but cannot reach it through finite cooling processes.
Liquid cryogen cooling: Cooling achieved by absorbing heat as a stored cryogenic liquid boils or evaporates. It can provide quiet cooling, unlike many mechanically driven systems.
Cryogenic engineering: The engineering of systems that produce, distribute, and safely manage very low temperatures. Instrument cooling depends on specialized materials, insulation, seals, and thermal design.

Linked from 5 pages