Annihilation radiation Annihilation radiation Annihilation radiation is a term used in Gamma spectroscopy for the gamma radiation produced when a particle and its antiparticle collide and annihilate. Most commonly, this refers to 511-keV gamma rays produced by a normal (negative) electron colliding with a positron. Annihilation radiation is not monoenergetic, unlike gamma rays produced by radioactive decay. The production mechanism of annihilation radiation introduces Doppler broadening. The annihilation peak produced in a gamma spectrum by annihilation radiation therefore has a higher full width at half maximum (FWHM) than other gamma rays in spectrum. The difference is more apparent with high resolution detectors,
Greenhouse effect heated) "greenhouse" with a cover of rock salt (which is transparent to infrared) heats up an enclosure similarly to one with a glass cover. Thus greenhouses work primarily by preventing convective cooling. Heated greenhouses are yet another matter, having an internal source of heating they leak heat out, which must be prevented. So it again makes sense to try to prevent radiative cooling through the use of adequate glazing. The anti-greenhouse effect is a mechanism similar and symmetrical to the greenhouse effect: greenhouse effect is about atmosphere letting radiation in, while not letting thermal radiation out, which warms the body