Types of radiation Flashcards
what happens when nuclear radiation contacts other atoms
dislodges electrons from them, and ionises them
some forms radiation are more ionising than others
what are alpha particles characterstics
2 protons + 2 neutrons
heavy, slow, 5% of speed of light (15,000,000m/s)
high ionising ability
low penetration ability
why does alpha radiation have high ionising ability
due to its significant mass + charge
a single alpha particles can ionise hundreds of thousands of atoms
what happens when alpha particles start colliding with other atoms
each interaction slows it down
eventually 2 electrons are absorbed from environment to become normal helium atom
how does alhpa particle have low penetrating power
alpha radiation can only travel a few centimetres in air, and is easily stopped by paper or the outer layers of skin.
what are beta particles characteristics
much lighter than alpha particles
travel 90% of speed of light
smaller charge +/- 1
moderation penetrating ability
moderate ionising ability
why does beta minus particle have moderate ionising ability
beta minus particles are fast moving electrons
due to reduced mass and charge, they only have moderate ionising ability
why do beta minus particles have moderate penetrating ability
due to negative charge of beta mins, they are repelled by atomic electron clouds.
they have glancing collisions and lose less energy from each interaction - which is why they have moderate penetrating ability
they can travel through few metres of air but can be stopped by 1mm of aluminium
what are beta plus partcles
fast moving positrons - charge of proton, mass of electron
or called antielectrons as they are the antimatter counterparts of electrons
what happens when a positron collides an electron
anhilation occurs, both particles are transformed into pure energy in the form of two gamma rays
why do beta plus particles have very high ionising ability and very low penetrating ability
it imediately annhilates the first electron it meets
what are gamma rays
electromagnetic radiation - very high frequency (high energy)
no mass, no charge
travel at speed of light which 3 x 10^8
what is the chance of gamma rays interacting with matter
very low
what ionising and penetrating ability does gamma rays have
low ioninsing ability
very high penetrating ability
what stops gamma rays
it can travel through air easily but are stopped by 40cm sheet of lead or 2m thick concrete
