Cold shield
Encyclopedia
A cold shield is a device to protect an object from unwanted heating by thermal radiation
or light. Usually it is a cooled object with low absorption and high reflectivity
.
It can be found in Molecular beam epitaxy
chambers to protect the growth areas from thermal radiation from hot sources.
In cryostat
s, a radiation shield protects a sample from infrared
radiation. An infrared detector
is protected from thermal background radiation outside its optical field of view
. These devices are usually cooled to the same temperature as the detector.
Cold shields are typically used in IR optical devices for military, scientific and industrial applications to protect IR sensors from stray IR radiation (lowering noise figures). Most coldshield applications require near instantaneous cooling, the low mass of the structure is very important.
Thermal radiation
Thermal radiation is electromagnetic radiation generated by the thermal motion of charged particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation....
or light. Usually it is a cooled object with low absorption and high reflectivity
Reflectivity
In optics and photometry, reflectivity is the fraction of incident radiation reflected by a surface. In general it must be treated as a directional property that is a function of the reflected direction, the incident direction, and the incident wavelength...
.
Molecular beam epitaxy
Molecular beam epitaxy is one of several methods of depositing single crystals. It was invented in the late 1960s at Bell Telephone Laboratories by J. R. Arthur and Alfred Y. Cho.-Method:...
chambers to protect the growth areas from thermal radiation from hot sources.
In cryostat
Cryostat
A cryostat is a device used to maintain cold cryogenic temperatures. Low temperatures may be maintained within a cryostat by using various refrigeration methods, most commonly using cryogenic fluid bath such as liquid helium. Hence it is usually assembled into a vessel, similar in construction...
s, a radiation shield protects a sample from infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
radiation. An infrared detector
Infrared detector
An infrared detector is a photodetector that reacts to infrared radiation. The two main types of detectors are thermal and photonic.The thermal effects of the incident IR radiation can be followed through many temperature dependent phenomena....
is protected from thermal background radiation outside its optical field of view
Field of view
The field of view is the extent of the observable world that is seen at any given moment....
. These devices are usually cooled to the same temperature as the detector.
Cold shields are typically used in IR optical devices for military, scientific and industrial applications to protect IR sensors from stray IR radiation (lowering noise figures). Most coldshield applications require near instantaneous cooling, the low mass of the structure is very important.