26.4 - Alpha, Beta and Gamma Radiation Flashcards
What is the property shared by alpha, beta and gamma radiation that allows them to be detected?
They are all ionising
What are they referred to as a collective?
Ionising radiation
How can alpha radiation be detected in the lab?
Using either a spark counter or an ionisation chamber
What did Rutherford show about alpha radiation?
It can be deflected by very strong magnetic and electric fields
What does this discovery therefore show about alpha radiation?
It is not actually radiation but consists of positively charged particles
What is an alpha particle?
A helium nucleus (helium without electrons)
What causes alpha particles to be highly ionising?
The fact that they have charge and a large mass
What does being ionising mean about the range of alpha particles in air?
It is very small
Why?
Because energy is used to ionise other particles, meaning it is losing energy and is quickly brought to rest
In the ionising process, what happens to alpha radiation?
It gains two electrons and forms an atom of helium gas
What apparatus is used to detect beta radiation?
A Geiger-Muller (GM) tube
What can stop beta radiation?
More than a few millimetres of aluminium/lead
If a strong magnet is placed near a beta source and GM tube, what is observed?
The count rate will drop
Why?
Because the beta radiation is deflected by the field
What does beta minus radiation consist of?
Fast-moving negatively charged electrons
