Kryostat

A kryostat, more commonly called a cryostat, is a device that maintains cryogenic temperatures for the preservation, handling, and study of specimens and components. In histology and pathology, cryostats enable the rapid production of thin frozen tissue sections by integrating a microtome inside a cooled chamber, typically operated around −20 to −30 °C. In physics, materials science, and engineering, cryostats provide stable temperatures from a few kelvin up to room temperature or higher, allowing experiments that require low-temperature conditions, such as superconductivity research and quantum materials studies.

Cryostats achieve low temperatures through cryogenic liquids or advanced refrigeration. Many laboratory cryostats use liquid nitrogen (about 77 K) or liquid helium (about 4 K) as a heat sink. Modern systems may employ closed-cycle coolers, such as pulse-tube or other mechanical refrigerators, to reach low temperatures without expendable cryogens. Some specialized cryostats are designed to work with strong magnetic fields or to couple to cryogenic detectors and sensors.

Key components include an insulated inner chamber for the sample, a cooling system (cryogen vessel or mechanical cooler), vacuum or multilayer insulation to minimize heat input, temperature sensors and a control system, and safety features such as venting and alarms. Operators must use appropriate personal protective equipment and maintain proper ventilation due to cryogen handling hazards.

Cryostats are essential in laboratories for tissue sectioning, materials characterization at low temperatures, superconducting and quantum experiments, and long-term cryogenic storage.