Atoms and nuclear radiation Flashcards
Why do isotopes give out radiation?
The nucleus gives out radiation to become stable or less unstable
What type of process is radioactive decay (in terms of determining when it will decay)?
It is a random process, which cannot be predicted
What is the activity of an isotope?
The rate at which a source of unstable nuclei will decay
What is the count rate and why is that different to the activity?
the count rate is the number of decays recorded each second. This is different from the activity because the detector doesn’t measure all the decays per second, some pass through or go in a different direction.
What is the difference between contamination and irradiation?
Contamination is when the radioactive isotope is on something it shouldn’t be on. Irradiation is when you expose an object to radiation but it doesn’t touch the object, it comes in contact with the radiation emissions but not the isotope itself.
Where does a beta particle come from and how is it formed?
A beta particle is an electron shot from the nucleus at very high speeds, nuclei do not contain electrons but when a neutron changes into a proton and an electron, it leaves one electron leftover which is the beta particle which is shot out.
What are gamma rays?
Gamma rays are electromagnetic waves
What is an alpha particle (in terms of structure)?
It has two protons and neutrons similarly to a helium atom.
What are alpha, beta and gamma particles stopped by?
Alpha is stopped by one sheet of paper
Beta is stopped by thin aluminium
Gamma is reduced by thick lead
Rank alpha, beta and gamma in terms of ionising power.
Alpha is strongly ionising
Beta is quite strongly ionising
Gamma is weakly ionising
What is a half life?
The amount of time it takes for the amount of nuclei to half
What is the risk of ionising radiation to humans?
It can increase the risk of cancer
What are the ways that alpha, beta and gamma can be dangerous?
Alpha is highly ionising however due to its low penetrating power it is stopped by the dead skin cells on the outer layer of the skin. Beta is quite penetrating and can enter the body. Gamma usually passes through the body and doesn’t collide with any particles
