Radiological Training for Accelerator Facilities
N Electromagnetic radiation.
N Charged particles.
DISCUSS special radiological surveys and techniques.
Skyshine is the radiation scattered from air molecules. Accelerator-produced skyshine is
usually neutron radiation, scattered after emerging more or less vertically from the shielded
enclosure. It can cause elevated radiation fields at ground level considerable distance from
Due to typical facility design, photon skyshine is usually less of a problem but is a
consideration, particularly where radioactive materials are stored.
Electromagnetic radiation (photons) may be classified into several categories.
High-energy photons (X- rays and gamma rays) may be produced by several mechanisms.
When electrons are decelerated, they emit bremsstrahlung "braking" radiation. These are
classified as X- rays. Also, the decay of subatomic particles may produce photons.
Electromagnetic cascades can develop when an electron (or positron) emits a photon that
has sufficient energy to produce an electron-positron pair. These particles produce more
photons, etc. The chain of interactions continues until the photons no longer have
sufficient energy for pair production (about 1 MeV).
Synchrotron radiation is a by-product of the acceleration process. When a charged particle
is bent in a magnetic field, it emits photons. The process depends greatly on the mass of the
accelerated particle; electrons produce much more synchrotron radiation at a given energy