Radiation Flashcards
What are the 4 types of radiation?
Alpha, Beta, Gamma and Neutrons
Is an electron positively or negatively charged?
Negatively charged
Is a proton positively or negatively charged?
Positively charged
Is a neutron positively or negatively charged?
Neutral (no) charge
What does a nucleus contain?
Protons and neutrons
Where does nuclear radiation come from?
Nuclear radiation comes from the nucleus, which is inside an atom
What charge is an alpha particle?
Positively charged
What charge is a beta particle?
Negatively charged
What charge is gamma
No charge
Are alpha particles large compared to beta?
Yes
Are electrons (gamma radiation) compared to alpha particles large?
No, electrons are very small and light
Is Gamma radiation a particle?
No, gamma radiation is an electromagnetic wave
If alpha, beta, and gamma radiation pass through an electric field what terminal would they move towards?
Alpha would move towards the negative terminal. Beta would move towards the positive terminal. Gamma is undeflected.
What is ionisation?
Ionisation is when electrons are added or lost from an atom and the atom is then called an ion
What is created when an electron is added?
A negatively charged ion is created
What is created when an electron is lost?
A positively charge ion is created
What can cause ionisation?
Nuclear radiation
Why an atom is neutral ?
Because the number of protons and electrons is equal
What type of radiation causes the most ionisation?
Alpha radiation
How much ionisation does beta radiation cause?
Beta radiation causes less ionisation than alpha, but more ionisation than gamma radiation
What is used to detect radiation?
A Geiger-Muller tube is used to detect radiation
What happens when radiation passes through a material?
The energy of the radiation is absorbed by the material
What absorbs Alpha radiation?
A few cm of air or a pice of paper
What absorbs beta radiation?
A few mm of aluminium
What absorbs gamma radiation?
A few cm of lead or several meters of concrete
What can pass through 5cm of lead?
Alpha: No
Beta: No
Gamma: No, but small particles will still get through
What is background radiation?
Radiation from our surroundings (it is normally at a very low level).
What are examples of natural sources of radiation?
Radon gas, Buildings and the ground, Soil and plants, Animals, Cosmic rays
What are examples of artificial sources of radiation?
Medical radiotherapy and diagnostics, Nuclear power, Nuclear missiles
What is the average annual background radiation in Uk?
2.2mSv
What is the annual effective does limit for members of the public?
1mSv
What is the annual effective does limit for radiation worker?
20mSv
Where should radioactive materials be stored?
They should be stored securely in lead lined containers
True or false: The time of exposure to ionising radiation should not be limited
False
What should sources be handled with?
Sources should be shielded and handled using tongs
What should radioactive sources never be brought close to?
Radioactive sources should be kept away from the body and never brought close to your eyes
What should the person doing the experiment wear?
Safety equipment
What can monitor radiation exposure?
Radiation exposure can be monitored using film badges
True or False: the radiation hazard symbol should be displayed
True
What is radiotherapy?
Radiotherapy is the use of radiation to treat cancer
What are the two main types of radiotherapy?
External and internal radiotherapy
What is external radiotherapy?
External radiotherapy is where several small doses of radiation are directed at the tumour from different directions
What happens to the surrounding organs and tissues during external radiotherapy?
Tissues and organs near the tumour should not be damaged since they receive a lower dose of radiation
What is internal radiotherapy?
This targets the cancer cells by either implanting radioactive material into the tumour (brachytherapy) or by giving the patient injections of radioactive liquid which is absorbed by the cancer cells
What is chemotherapy?
Chemotherapy is the use of drugs to kill cancer cells
Is chemotherapy a form of radiotherapy?
Chemotherapy is not a form of radiotherapy
What is half life?
The half life is the time taken for the activity of a radioactive source to fall to half of its previous value
What are industrial applications of nuclear radiation?
Gauging devices, Non-destructive testing, Sterilisation, Scanning
What are gauging devices?
The amount of radiation passing through a material can be measured. This gives an indication of the thickness of the material and or how much moisture it contains
What is non-destructive testing?
A radioactive source can be placed on the inside of a pipe where a weld has been made. Photographic film on the outside can detect any defects in the weld.
What is sterilisation?
Gamma radiation can be used to sterilise supplies used in hospitals or be used to kill bacteria on food.
What is scanning?
People and luggage are scanned at airports to prevent dangerous items being carried on board a plane
What are the two types of fission reaction?
Spontaneous fission
Induced fission
When does fission occur?
Fission occurs when a heavy nucleus disintegrates leaving two or more smaller pieces plus two or three neutrons
what type of fission happens when the nucleus is unstable?
Spontaneous fission
What is induced fission?
Induced fission is where the reaction is triggered when a fast neutron collides with the nucleus, making it unstable
Where is induced fission used?
This is used in nuclear power stations. When the nucleus splits some of the mass is ‘lost’-it has been converted into energy. This is in the form of heat
What is the fission chain reaction?
The neutrons released by the fission reaction are fast moving and go on to collide with more nuclei
What is used to slow the fission chain reaction down?
A material such as graphite is used to slow them down and increase the chance of further reactions happening
What is used to manage the fission chain reaction?
The reaction is managed using other materials e.g. boron, which absorb some of the slow neutron
What happens if the fission chain reaction is not kept under control?
If the reaction is not kept under control it will become larger and larger- potentially creating a bomb
What is nuclear fusion?
Nuclear fusion is where two or smaller nuclei combine to form a larger nuclear
True or false: nuclear fusion is the same as nuclear fission
False: Nuclear fusion is the opposite of nuclear fission
Where does fusion take place?
Fusion takes place in the Sun and other stars
Fusion- what happens when the nuclei fuse?
When the nuclei fuse some of the mass is ‘lost’- it has been converted directly into energy. This is in the form of heat
True or false: nuclear fusion cannot be used to generate electricity
False: nuclear fusion can be used to generate electricity
Nuclear fusion and power generation- would it be safer than nuclear fission? Why?
It would be safer than nuclear fission because there is no chain reaction and there would be little or no nuclear waste and no greenhouse gases. The fuel costs would also be low
When a fusion reaction takes place what is created?
When a fusion reaction takes place a plasma is created
How hot is a plasma?
A plasma is extremely hot- 150 million degrees Celsius
How is a plasma contained?
A plasma must be contained by a doughnut shaped magnetic field
Why must a plasma be contained?
To prevent it coming into contact with anything
Is containing a plasma a complex process?
This is a complex process. Very high energy is also needed to reach these high temperatures
Are fusion reactors a thing?
Scientists are developing fusion reactors but they are still at an experimental stage. In the future we may be able to use fusion reactors to generate electricity
How is a Geiger-Muller tube used detect radiation?
When it is connected to a counter the amount of radiation can be measured. It does this by detecting ionisation of the gas inside the tube
