Radiation Protection Glossary

A radiation protection glossary for Radiation Protection Supervisors (RPS), Radiation Protection Advisers (RPA) and anyone else interesting in radiation safety terms and definitions. The glossary is a mixture of health physics , phrases related to radiation protection legislation, transport, practical safety, technical terms and similar.

Search the Glossary by either clicking on a letter or typing a keyword into the search box. This glossary is relational so when looking at one term you can click through to other related terms as required.

For formal advice, see our Radiation Protection Adviser pages. 

X-Rays

X-rays are part of the Electromagnetic spectrum. They are a penetrating form of electromagnetic radiation and consist of quantum's of energy (Photon). X-rays are commonly produced by the excitation of atomic Electrons, by firing electrons between a high potential difference towards a target (which is the principle of an x-ray machine).

The target electrons are excited, and as they de-excite x-ray photons are produced. X-rays can also be produced as a result of Bremsstrahlung or by nuclear reactions. X-rays have many uses including medical imaging and industrial quality assurance.

Whilst commonly stated (or assumed) that gamma rays are emitted by certain radioactive materials, x-rays can also be emitted if the process involves photons being produced within the electron orbit (cloud) around the nucleus (such as in the case of electron capture). An example is the radioactive substance I-125 which emits gamma rays during decay and x-rays from the post decay product(Te-125).

A man who dares to waste one hour of time has not discovered the value of life

– Charles Darwin -