photon gamma

CONT: Les photons gamma très pénétrants permettent de réaliser de véritables radiographies des matériaux les plus denses. Cette technique [gammamétrie] est appliquée depuis quelques années à la détermination de la densité et de l'humidité des sols.

CONT: The method by which incident radiation interacts with the medium to cause ionization may be direct or indirect. Electromagnetic radiations (X rays and gamma photons) are indirectly ionizing; that is, they give up their energy in various interactions with cellular molecules, and the energy is then utilized to produce a fast-moving charged particle such as an electron. It is the electron that then secondarily may react with a target molecule. Charged particles, in contrast, strike the tissue or medium and directly react with target molecules, such as oxygen or water. These particulate radiations are directly ionizing radiations.
CONT: The third step is to fuse two tritium nuclei into one helium and two proton products. The end result of fusing four hydrogen nuclei (protons) is one helium nucleus, and two gamma ray photons, and two electron neutrinos, and kinetic heat energy.
OBS: Gamma rays: A very penetrating electromagnetic radiation emitted from a nucleus of an atom during radioactive decay. Radiation: An emission of energy in the form of photons (gamma, x-rays) or particles (alpha, beta, positron, neutron radiation). Photon: A type of radiation in the form of an electromagnetic wave, having zero mass and zero charge.