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,
Radiation sensitivity of the radiation effect depends on the stability of the induced physical and chemical change. Physical radiation effects depending on diffusion properties can be thermally annealed whereby the original structure of the material is recovered. Chemical radiation effects usually cannot be recovered. Radiation sensitivity Radiation sensitivity is the susceptibility of a material to physical or chemical changes induced by radiation (see also: radiation effect). Examples of radiation sensitive materials are silver chloride, photoresists and biomaterials. Pine trees are more radiation susceptible than birch due to the complexity of the pine DNA in comparison to the birch. Examples of radiation insensitive