Ionising radiation Flashcards
What are some examples of ionising radiation?
Gamma rays
X-ray
Ultra violet
What is ionising radiation?
any type of particle or electromagnetic wave that carries enough energy to ionise (remove electrons from an atom)
What 3 types of radiation are there?
Alpha
Beta
Gamma
What is ionising power of alpha radiation?
very high
What is ionising power of beta radiation?
weak
What is ionising power of Gamma radiation?
weak
What is the range in air of alpha radiation?
5cm
What is the range in air of beta radiation?
20cm
What is the range in air of gamma radiation?
long
What is the penetration of alpha radiation?
Stop by skin cell layer
Paper
5cm
What is the penetration of beta radiation?
Low penetration - stopped by aluminium
What is the penetration of gamma radiation?
Very high velocity and low wave length means it has high penetration
Stopped by Lead
What are some sources of radiation?
Radon gas
Space
Earth
Human
Medicine (X-ray and nuclear)
Consumer products
How much of radiation is form natural sources?
81%
How much radiation is from human sources?
19%
What are the main natural sources of radiation?
Igneous rock ,granite
Uranium rich sedimentary rock e.g. sandstone
How does granite and sandstone release radiation?
When granite is weathered radon gas (trapped inside) can easily escape
When sandstone is weathered uranium can be released into water
What are the 6 main uses for radioactive material?
Power industry
Scientific research
Medical uses
Food industry
Dating of rocks
Industry
How does the power industry uses radioactive material?
Uranium in nuclear power generation
How is radioactive material used in scientific research?
Radioactive isotopes used to see pollution movement
What are the medical uses of radioactive material?
X-rays
Sterilising equipment
Cancer treatment
How is radioactive material used in the food industry?
Irradiating food to kill bacteria and fungi
What can radioactive material be used to date?
Rocks
Bones
Pottery
What is used to date things using radioactive material?
Carbon 14
How is radioactive material used in industry?
Strengthening polymers
What 4 factors affect the danger of radiation?
Range and penetrating power
Half life of the radiation
State of matter
Internal or external route into body
What route into the body is worst for radiation internal or external?
Internal as more organs to pass through
What is half life?
time it takes for half of the unstable nuclei in a sample to decay
What is the process of ionisation?
An ionising radiation knocks electrons off atoms disrupting the structure of the molecules
What is the problem with free radicals?
They move quickly, are highly reactive and can damage molecules such as proteins and DNA
What is the problem with free radicals affecting proteins or DNA?
Proteins- cell death or enzyme disruption
DNA- Mutations (tumours)
What type of radiation is released by radon gas?
Alpha
How can Radon gas affect lung cells?
If alpha particles are inhaled
What is the second biggest cause of lung cancer?
Radon gas
What is the length of time of acute radiation exposure?
Short term
What is the length of exposure for chronic radiation?
Long term
What is the level of dosage for acute radiation exposure?
Large dose
What is the level of dosage for chronic radiation exposure?
Small dose
What are the effects of acute radiation poisoning?
Haemorrhages (internal bleeding)
Hair loss
Death
What are the effects of chronic radiation poisoning?
Gonadic and somatic mutations
What is risk benefit analysis for radiation?
Using benefit poses risks if benefit outweighs risk then it’s justified
What is the Separation associated with risk benefit analysis with radiation?
People who endure the risk may not be the same as those who take it e.g. uranium miners may not be in the same country as those who receive the electricity produced from it
What are the problems with risk benefit analysis?
Uncertainty about long term effects of exposure to low level radiation
Temporal mismatch
What is temporal mismatch?
we may not understand the risks of using radioactive material until decades later
What are some control methods for ionising radiation?
Protective clothing
Remote handling using (reduce human contact)
Closed sources - radioactive material kept in sealed container
Minimising exposure period
Maximise distance from source
Why might air crew not be able to properly protect themselves from cosmic radiation?
As full protective clothing it might frighten passengers thus reducing sales
What does doubling distance from source do to exposure?
Reduces it by 75%
How can radioactive effluent be monitored?
CPA- critical pathways analysis
What does CPA identify?
possible environmental routes, radioactive materials may take after release
What can we not assume with CPA?
that any pollutant released into the environment will be dispersed and diluted so that the risks are reduced to low levels of significance
What factors will inform CPA?
Physical state (solid. liquid gas)
Density
Meteorlogical/ water currents
Geology (porous/ permeable)
Bioaccumulation
Half-life
What can be done to asses contamination risk on humans?
Critical groups
What are critical groups?
members of the public who are considered particulalry at risk of radiation because of job. location, food or water source.
When using critical groups how do you know if action needs to be taken?
if the critical group are not being exposed to too much no one else will
What would the critical group be for a nuclear power plant?
Those who live near the station and eat local food
What local food would be assessed as part of CPA?
Milk
Fruit
Honey
Who will not be included as part of critical group monitoring?
occupational workers who are monitored in different ways
What 3 agencies monitor radiation pollution?
Department for environmental food & rural effects
Food standards agency
Environment agency
What do department for environmental food & rural affects monitor? (radiation)
discharge from power stations and radon gas within houses
What does the environment agency monitor? (radiation)
routinely monitors radiation levels in soil, grass, dust, water and air
What does the food standards agency monitor? (radiation)
radiation levels in food across UK (only UK grown near potential source)
What is the problem with using CPA to set acceptable levels?
Assumes everywhere is safe
Assumes all pathways have been accurately predicted
