Applications in particle physics
The term bolometer is also used in particle physics to designate an unconventional particle detector. They use the same principle described above. The bolometers are sensitive not only to light but to every form of energy. The operating principle is similar to that of a calorimeter in thermodynamics. However, the approximations, ultra low temperature, and the different purpose of the device make the operational use rather different. In the jargon of high energy physics, these devices are not called calorimeters since this term is already used for a different type of detector (see Calorimeter (particle physics)). Their use as particle detectors was proposed from the beginning of the 20th century, but the first regular, though pioneering, use was only in the 1980s because of the difficulty associated with cooling and operating a system at cryogenic temperature. They can still be considered to be at the developmental stage.
Microbolometers
A microbolometer is a specific type of bolometer used as a detector in a thermal camera. It is a grid of vanadium oxide or amorphous silicon heat sensors atop a corresponding grid ofsilicon. Infrared radiation from a specific range of wavelengths strikes the vanadium oxide or amorphous silicon, and changes its electrical resistance. This resistance change is measured and processed into temperatures which can be represented graphically. The microbolometer grid is commonly found in three sizes, a 640×480 array, a 320×240 array (384×288 amorphous silicon) or less expensive 160×120 array. Different arrays provide the same resolution with larger array providing a wider field of view Larger, 1024×768 arrays were announced in 2008.