How does exposure to radiation make ordinary material radioactive?

[Silviu]

Hello! How can ordinary material become radioactive, if exposed to radioactive sources? I read that Marie Curie's notes are still radioactive and I am not sure I understand how. As far as I know gamma and X-rays can excite or ionize an atom or excite a nucleus. How does this make the radiated material to become radioactive?

 

[phinds]

maybe this will help

https://en.wikipedia.org/wiki/Induced_radioactivity

 

[mfb]

I read that Marie Curie's notes are still radioactive and I am not sure I understand how.

Probably from direct contamination, pieces of radioactive samples stuck to the notes.
Induced radioactivity is much weaker.

 

[PSRB191921]

Hi,
mfb is right, Marie Curie notes are radioactive because of contamination and not due to induced activity. To obtain induced activity, neutrons or particles (e.g. ions) of high energy are required. It is possible to activate with high-energy photons (threshold effect)
PSR

 

[vanhees71]

Legend has it that Marie Curie carried a sample of Ra in her pocket. It's no surprise that she got cancer!