Please enable JavaScript.

Coggle requires JavaScript to display documents.

Radiation - Coggle Diagram

- - - - this means that they are more likely to decay
      - An isotope will decay because of the imbalance between neutros and protons
      - Ionising radiation
        
        This type of radiation happens when an unstable isotope releases particles so it can be balanced.
        
        The process where an atom releases particles to become balanced is called radioactive decay
        
        Racioactive decay
        
        The process in which an unstable isotope releases particles to become stable
        
        Radioactive decay is a random process which can't be triggered and is not a chemical reaction
        
        Ionising is a type of radioation which can be harmful
        
        Nuclear radiation
        
        A type of radiation which originates from an atomic nuclei
  - - - Alpha radiation is a type of nuclear radiation which involves the isotope releasing an alpha particle
      - An alpha particle consists of 2 protons and 2 neutrons which is the same as a helium particle
      - Alpha radiation causes the mass and atomic numberof an isotope to change
        
        exp: 238 92 U--> 234 90 Th + 4 2 He
        
        https://nuclear-power.com/wp-content/uploads/2018/08/Alpha-Decay-Alpha-Radioactivity-definition.png
        
        charge/ Atomic number will decrease by 2
        
        mass number will decrease by 4
      - Properties
        
        Highly ionising
        
        not very penetrating (can be stopped by a sheet of paper)
    - - Beta radiation will cause a neutron to turn into a proton and will emit a fast moving electron
      - This type of radiation will cause the atomic number to change
        
        The atomic number will increase by 1
        
        exp:3 1 H--> 3 2 He + 0 -1 e
      - Properties
        
        medium penetrating power (can be stopped by thin aluminium )
        
        medium ionising power
    - - Gamma radiation is a high-frequenct electromagnetic radiation
      - gamma radiation has no charge and no mass as it is a wave
      - It doesn't change the mass or atomic number of an isotope
        
        exp:209 84 Po--> 209 84 Po + 0 0 (γ)
  - - - Geiger-müller tube
        
        The most common method to measure radioactivity
        
        It is a device which absorbs radiation and transmits an electrical pulse which is then displayed in a count rate
        
        The higher the frequency of clicks the more radiation detected
      - Photographic film
        
        Photographic films detect radiation by becoming darker when it absorbs radiation, similar to when it absorbs visible light
    - - Radiation is a natural phenomenon which will allways exist
      - The radiation that exists around us all the time
      - This graph shows te most common sources of background radiation
        
        https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1080/https://cdn.savemyexams.com/uploads/2021/06/8.1.5-Background-Radiation-Chart.png
      - background radiation most commonly comes from radon gas
        
        Airborne radon gas comes from rocks in the ground, as well as building materials
        
        This is due to the presence of radioactive elements, such as uranium, which occur naturally in small amounts in all rocks and soils
    - - Radiation which has been created by humans
      - Includes
        
        nuclear waste
        
        nuclear fallouts from nuclear weapons
        
        nuclear medicine (x-rays)
        
        Nuclear accidents
  - - - The rate at which an unstable nucelli decays
      - It is measured in becquerels (Bq)
        
        1 Bq = 1 nucleous in the source decaying per second
      - The activity of a source will decrease over time
      - radioactive decay plotted in a graph
        
        https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1080/https://cdn.savemyexams.com/uploads/2021/05/23.2-Radioactivity-Fluctuations.png
    - - The process in which an unstable atomic nucleous loses energy through radiation to become stable again
    - - The time it takes for the number of nuclei of a sample of radioactive isotopes to decrease by half
      - Half life veries between each isotope
      - half life is a way to find aut the rate in which an isotope decays
      - The rate in which half life happens will allways be constant
        
        exp: 100%-->3h hours pass--> 50%--> 3 hours pass--> 25%
      - Half life can be used using a graph
        
        https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1080/https://cdn.savemyexams.com/uploads/2021/08/6.2.10-Half-life-Graph.png
- - - - tongs r gloves to not touch the source directly
      - wearing protective clothing
      - shielding container
      - limiting the time of the source outside the shielding container
  - - - Alpha radiation would be very dangerous in the body
    - - Gamma sources are more penetrating meaning they can be more dangerous outside the bodt
- - - - This is why it is hard to replicate in earth
    - - Instead of using a fission reactor, scientist want to achieve a fussion reactor as it will produce more energy. This technology is still not stable enough to be used.
      - Advantages of using fussion reactor
        
        Doesn't create long term waste products
        
        The fuel used in fusion is more common than fission
        
        Will prodce more energy than fission reactor
      - Disadvantages of using a fusion reactor
        
        The conditions for nuclear fusion are a lot harder to reach.
    - - requires
        
        very high temperatures
        
        very high pressure
      - The requirements are caused by the strong electrostatic repulsion
        
        This means a lot of kinetic energy is needed for the 2 nucleus to get close enough so fusion can happen
  - - - Most common fissile materials are uranium and plutonium
    - - Induced fission is acomplished by laucnhing a neutron to the isotope. This will result on the neutron being absorbed by the isotope and turning it more unstable
    - - IN this case a neutron is fused with uranium-235 to form uranium-236
        
        Uranium-236 is very unstable and will split imediately
        
        This will create
        
        3 neutrons
        
        2 daughter nuclei
      - https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1080/https://cdn.savemyexams.com/uploads/2021/07/8.4.5-Induced-Fission-Uranium.png
    - - This is because energy is transferred from the nuclear potential energy stored in the original nucleus into the kinetic energy of the products
        
        In a nuclear power station, this energy can be harnessed and converted into electrical energy
    - - Chain reaction
        
        When nuclear fission happens 2 or 3 neutrons are released
        
        These new neutron will cause another fission reaction
        
        This process will be repeated in a chain reaction
        
        A neutron emitted from the splitting of a nucleus causes further nuclei to split and the neutrons emitted from these cause further fission reactions
        
        For a chain reaction to be maintained, there must be a minimum amount of fissile material called the critical mass
        
        If the mass of fissile material exceeds the critical mass, the rate of reaction accelerates
        
        This can cause a huge and uncontrolled release of energy, i.e. a nuclear explosion
      - nuclear reactor
        
        diagram
        
        https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1920/https://cdn.savemyexams.com/uploads/2021/07/8.4.6-Nuclear-Reactor-Components.png
        
        A process where nuclear fission is used to create electricity with turbines
        
        controlled factors in a nuclear reactor
        
        numbers of free neutrons in the reactor
        
        controlled by control rods
        
        The control rods absorb neutrons to control free neutrons in the reactor.
        
        The control rod is made of a material which will absorb the neutrons without becomind dangerous
        
        The number of neutrons absorbed will be controlled by the depth of the control rods in the reactor
        
        Lowering the rods will result on the rate of fission to decrease
        
        Raising the rods will cause fewer neutrons to get absorbed, increasing the rate of fission
        
        The energy of the free neutron
        
        Controlled by moderator
        
        The moderator slows down the neutrons to decrease the rate of fission
        
        It is made of graphite which surround the nuclear core
        
        The neutrons slow down when they collide with the moderator, decreasing their speed
        
        The objective of slowing down the neutron is to reach thermal equilibrium
        
        This will ensure that the neutrons can react efficiently with the reactor core
        
        Parts of a nuclear reactor
        
        water circulator
        
        uses the heat of the nuclear reactor to produce steam to turn a turbine
        
        Used to cool down the reactor
        
        fuel rods
        
        Long metal tubes which contain fissionable material
        
        Radiation shielding
        
        A protective shield around the reactor to stop radiation from getting out of the reaction.
- - - - 1.https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1080/https://cdn.savemyexams.com/uploads/2021/07/4.2.3-Smoke-alarm-diagram-1.png
      - 2.https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1080/https://cdn.savemyexams.com/uploads/2021/07/4.2.3-Smoke-alarm-diagram-2.png
      - Alpha radiation is used in smoke detectors
        
        Alpha radiation ionises the air creating a current
        
        The smoke emitter is blocked by smoke causeing a sensor to trigger
    - - When creating things such as aluminium foil a beta source is used. The number of beta particles that trespass the foil are used to determine its thickness
      - If the material gets thicker, more particles will be absorbed, and the count rate will decrease
      - f the material gets thinner, fewer particles will be absorbed, and the count rate will increase
    - - Radiation can be used to kill cancerous cells
      - As well gamma radiation can be used to detect cancer.
    - - Gamma radiation can be used to sterilise medical equipment
      - Gamma radiation is mainly used because
        
        most penetrating
        
        It has the ability to erradiate all sides of the instrument
        
        Can be sterilised througha package.
      - gamma radiation can be used to kill microorganisms in food making it last longer