GC: n

CT: If you are not familiar with working around radiation or radioactive material, the terms and concepts may confuse you at first. Let’s look at some of the properties of radiation and radioactive material.

• Radiation – Radiation is energy in the form of waves or particles given off during radioactive decay, or as a consequence of certain physical processes that we can control. Examples of these are x-ray machines and particle accelerators.
• Wave radiations include gamma and x-rays. A common term used to describe this type of radiation is photon radiation.
• Particle radiation can consist of charged or uncharged particles which are emitted with very high velocity.
• Radiation travels from its source at very high speed, and depending on the type, may be able to penetrate easily through very dense materials.
• Radioactive material – Any material that contains radioactive (unstable) atoms. Radioactive materials are everywhere. Usually, we only encounter them in very small amounts. Since radioactive material contains unstable atoms, it emits radiat ion.
• Radioactive contamination – Not all radioactive material is considered “contamination”. Contamination is radioactive material that is in a form or location which may allow it to be spread to unwanted locations. Many radioactive sources are sealed or are in a form that isolates the material from potential spread. Contamination may be Fixed, Transferable (loose), or Airborne.

It is important to note that exposure to radiation does not result in contamination of the worker. You may become contaminated only through direct contact with material that has removable radioactive material, or by working in areas where this contaminated material is handled.

• Radioactivity – Radioactivity is the process od unstable (or radioactive) atoms becoming stable by emitting radiation. The radioactive decay process involves fundamental physical constants which enable us to characterize and measure radioacti ve materials very accurately.
• Radioactive half-life – Radioactive half-life is the time is takes for one half of the radioactive atoms present in a given sample to decay. The half-life of a particular isotope is a constant, and depending on the isotope it may range from a fraction of a second to millions of years. After seven half-lives the activity will be less than 1% of the original activity.

S: https://www.jlab.org/div_dept/train/rad_guide/rad.html (last access: 19 February 2015)

N: 1. radioactive (adj): 1898, from French radio-actif, coined by Pierre and Marie Curie from radio-, comb. form of Latin radius (see radiation) + actif “active” (see active).
contamination (n): early 15c., from Latin contaminationem (nominative contaminatio), noun of action from past participle stem of contaminare (see contaminate). Figurative sense is from c.1620; specifically of radioactivity from 1913.
2. A radioactive substance in a material or place where it is undesirable.

S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=radioactive+contamination&searchmode=none (last access: 19 February 2015). 2. TERMIUM PLUS (last access: 19 February 2015).

SYN: contamination

S: GDT (last access: 19 February 2015); TERMIUM PLUS (last access: 19 February 2015).

CR: environment, nuclear energy, pollution , radioactive waste, radon , X-rays.