9.4 Ionising Radiation Flashcards
What are the 4 types of ionsing radiation ?
Alpha
Beta plus
Beta minus
Gamma
Another name for ionizing radiation ?
Nuclear radiation
How can we detect alpha radiation ?
Using a spark counter or an ionization chamber
What is alpha radiation absorbed by ?
- few cm of air
- paper
Can alpha particles be deflected by a magnetic field?
Yes , due to being charged
Can alpha particles be accelerated by electric fields?
Yes due to being charged
What is the relative charge of an alpha particle?
+2
What is the nature of an alpha particle?
Helium nucleus
- 2 protons and 2 neutrons
What is the mass of an alpha particle?
4u
What is u ?
Atomic mass unit
Why does alpha have a strong ionsing ability ?
Due to strong mass and charge they can pull electrons off atoms hence easily absorbed as passes through matter so they also dont travel far
What is alpha particles speed compared to beta and gamma?
Lower speed than both beta and gamma
What can we detect beta radiation with?
Geiger Muller Tube connected to scaler or rate meter
Why cant a geiger muller tube detect alpha radiation?
Alpha cannot penetrate through the thin mica windows
What is the nature of a b minus radiation ?
Electron like
What can b minus particles travel through
- 50 cm of air
- 3mm of aluminium
Can a b minutes radiation/particles be deflected using a magnetic field?
Yes
Beta minus and electric field
The particle will be affected
What is the charge of a b minus particle
-1
What is the mass of a b minus particle
Negligible
Why does b minus radiation cause less ionization than alpha ?
Less charge and mass
Why is b minus particle more penetrative compared to alpha
Lower ionization and greater speed so can penetrate more until all energy is used up
What is the b minus speed compared to alpha and gamma
Faster than alpha but slower than gamma
How can we show that a magnetic field affects a b minus radiation?
Have a magnetic field perpendicular to direction of travel of beta radiation towards a GM tube.
The count should be lower with magnetic field than without
What is gamma radiation ?
High frequency em radiation
What is em radiation?
Photons
What is a photon
Bundle of em energy
How ionising is gamma radiation ?
Weakly ionizing as a photon has to directly collide with a particle for ionization to occur
What is gamma radiation absorbed by?
- many cm of lead
- several m of concrete
How far can gamma travel?
Greater distances compared to alpha and beta. Due to low ionization it takes a long time for all energy to be transferred.
Is gamma radiation affected by fields (magnetic and electric)
No
What is the charge of gamma radiation ?
None
What is the speed of gamma radiation
Speed of light
What is the mass of gamma radiation?
None
Why do beta minus particles deflect more than alpha?
Have lower charge but also much lower mass making then easier to deflect
What is the nature of a B plus particle?
Positron
What is the charge of a b plus partickle
+1
What is the mass of b+ ?
Negligible
What is the range of a b + particle /radiation
Gets instantly annihilated by electrons so zero range
Where does ionising radiation come from ?
Unstable nuclei of radioactive elements
