Ionising radiation Flashcards
What is ionizing radiation
- radiation with enough energy to remove tightly bound electrons from the orbit of an atom
- causing the atom to become charged
Nature of alpha
- charged
- made of 2 protons + 2 neutrons
- heavy
- slow
What is alpha stopped by
- clothing
- dead skin
Health risks of alpha
- ingested - particles absorb in a small mass of tissue
- creates increased damage and increase risk of radical interactions
Nature of beta
- charged
- fast
- light
What is beta stopped by
- thin layer of substance
- e.g aluminum
Health risk of beta
- sources near body still pose a risk
Nature of gamma
- made up of packets called photons
- light
- no charge
What is gamma stopped by
Dense materials e.g. lead
Health risks of gamma
Lower danger
Nature of neutrons
No electric charge
Heavier than protons
What are neutrons stopped by
Thick materials that are rich in hydrogen e.g. water
Health risks of neutrons
Very dangerous
High risk after they’ve been absorbed
Definition of half-life
Time taken for the radioactivity of a specified isotope to fall to half its original value
Which pollutant property does half-life determined
Persistence
Why do you think everybody’s risk from each source is not equal
People may live in different geographical areas, so other areas might have less
Different age groups have different medical conditions
Definition of contamination
Physically carrying radioactive materials, which when they release radiation, may cause exposure
Definition of exposure
Absorption of ionising radiation
What is the difference between exposure and contamination
Exposure is about the radiation dose received, while contamination is about the presence of radioactive material
Who are most at risk from radiation exposure
Children
Pregnant women
Plants
People living in granite areas
Most common uses of radioactive materials and ionising radiation
Research e.g tracers
Medical appliances e.g x-rays
Nuclear power generation
Close courses
Prevent workers from coming into direct contact with the source, by enclosing the source in a container
Absorbers
Materials should be used as barriers to prevent radiation reaching workers.
Thickness etc will depend upon type of radiation involved and space available
Distance from the source and the inverse square law
Inverse square law - distance from the source increases = drop in exposure
1/distance^2
Reducing time exposed
Working arrangements should minimise time a worker is close to a source of
Monitoring workers
Personal dosemeters which gives a reading of current exposure
Air monitors to detect atmospheric particles, including alpha - emitters
How can we measure radiation
Becquerel - measures activity of the source
Gray - measure of absorbed dose
What ionising radiation was released in the Chernobyl incident
Iodine - 131, cesium - 134 and cesium 137
What were the effects of the Chernobyl incident on human health
Thyroid cancer
Radiation sickness ( vomiting and headaches )
What lessons have been learnt? What controls have been put in place to stop another incident like this taking place? (Chernobyl incident)
Public awareness
Effective communication
Medical care
Emergency preparedness
Critical pathway analysis definition
Predict the route a pollutant will take
Identify where it might become problematic
Important pollutant factors in CPA
Physical state (solid,liquid,gas?)
Density (how far it travels)
Weather conditions (wind direction and speed)
River flow or ocean current (strength and direction)
Nature of environment (geology)
PH and O2 availability (solubility)
Ability to bioaccumulate and biomagnify
Half-life
What information does environmental sampling disclose
Presence or absence of pollutant
Type and concentration of pollutant
Materials that are often sampled for radioactive materials
Vegetation ,soil,water,meat,fish,dairy
Why are these materials often chosen for environmental testing
Most likely to be contaminated
Likely to enter the food chain
Critical group monitoring definition
Pollutant incident where people are identified most at risk
If okay, make an assumption that everyone is
Why is critical group monitoring used
Information about radiation and its health effects can be produced
Public health management
