What is the Emissivity of a Black Body?

Answer: Emissivity is the ratio of the energy emitted from the surface of a material to the energy emitted at the same temperature and wavelength from a perfect emitter called a blackbody. The emissivity of a black body is 1.

In FT-ICR MS, infrared radiative blackbody dissociation is done by heating the vacuum chamber around the analyser cell. When this happens, the walls of the analyser cell give off infrared photons from a black body, which are absorbed by the trapped ions. When thermal infrared radiation is absorbed, it raises the temperature of the ions in the ICR cell, which causes the ions to break apart.