Gamma rays (denoted as γ) are a form of electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions, such as electron-positron annihilation or radioactive decay. Gamma rays are generally characterized as electromagnetic radiation having the highest frequency and energy, and also the shortest wavelength (below about 10 picometer), within the electromagnetic spectrum. Gamma rays consist of high energy photons with energies above about 124 keV.

Hard X-rays overlap the range of "long"-wavelength (lower energy) gamma rays, however the distinction between the two terms depends on the source of the radiation, not its wavelength; X-ray photons are generated by energetic electron processes, gamma rays by transitions within atomic nuclei.

Due to their high energy content, gamma rays can cause serious damage when absorbed by living cells.

Gamma Ray is a power metal band from north of Germany, founded by former Helloween guitarist, singer, and songwriter Kai Hansen.

Founded in 1989 by Kai Hansen after leaving Helloween , Gamma Ray borrowed straight from the Helloween classics, and continued to pioneer Hansen’s style of power metal. After four years with Helloween , Kai Hansen decided to leave the band at the height of their career. He then went on to do some studio work with Blind Guardian . Kai and his friend Ralf Scheepers from Tyran’ Pace decided to start a project. They recruited bassist Uwe Wessel and drummer Mathias Burchard. The resulting sound w