eli5:What does it mean when an object is irradiated?

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Does this object now also give off radiation/become radioactive?
For example, if a dust particle were to be hit by a ton of gamma radiation, would this piece of dust become radioactive?
Edit: what does it mean when the piece of dust becomes contaminated?

In: Physics

3 Answers

Anonymous 0 Comments

Irradiation just means that something has been hit by radiation. Could be photons, like uv radiation, could be neutron radiation from a nuke. What happens after depends on what the type of radiation is, as well as the quantity.

What you seem to be referencing is irradiation in the context of something becoming radioactive after being irradiated. This is something that just gamma rays won’t do. Gamma rays will destroy lots of things, especially living organisms dna, but even huge quantities of gamma radiation will just turn that dust into plasma. After the gamma rays are removed you don’t get any nuclear radiation from the dust. Though it will be quite warm. In fact gamma rays are used like this to sterilize things after being sealed like bandaids, and medical needles.

For something to become radioactive you would have to hit it with neutron radiation. The neutrons hit other atoms and combine to form new nuclei that are usually unstable. These unstable nuclei will then decay into more stable nuclei after some amount of time, releasing energy in the process.

Anonymous 0 Comments

Well, technically “irradiated” can just mean you’ve shone a bright light on an object. Assuming you’re talking about ionising radiation (e.g. the stuff that can kill you), AFAIK the only way that can make a material permanently radioactive is via a process called neutron absorption, where the atoms of the material take extra neutrons in and get turned into (likely radioactive) isotopes. Gamma radiation can’t do that.

Anonymous 0 Comments

Radtech here, a material is either radioactive or not, and can be made radioactive through intense neutron bombardment to change the overall atomic structure to create an isotope. If a material inherently gives off radiation then it is radioactive, if it is covered by a material that is radioactive then it is contaminated, if it has received a dosage of radiation then it has been irradiated.

If you have received enough neutron radiation to become radioactive then you’re going to have a baaaaad time. I’ve seen what a cobalt-60 source will do to a person… eurgh i’d hate to see neutron.