Radiation

• Nuclei with too many, or too few, neutrons do exist naturally but are unstable and will decay by emitting radiation.
• Alpha decay causes the mass number of the nucleus to decrease by four and the atomic number of the nucleus to decrease by two. It also has a helium-4 nucleus
• What is beta emission?

  If the nucleus has too many neutrons, a neutron will turn into a proton and emit a fast-moving electron.
• label.

  A) Alpha

  B) Beta

  C) Gamma

  D) 4

  E) 2

  F) e

  G) 0

  H) -1

  I) 0

  J) 0

  
• Beta decay causes the atomic number of the nucleus to increase by one and the mass number remains the same.
• To cool down after radiation, the nucleus will emit electromagnetic waves. This is gamma radiation.
• Neutron emission causes the mass number of the nucleus to decrease by one and the atomic number remains the same.
• fill in gaps

  A) paper

  B) aluminium

  C) lead

  D) high

  E) low

  F) very low

  G) cm

  H) m

  I) km

  
• All types of radioactive decay can be detected by a Geiger-Muller tube. The radiations ionise the gas inside and the resulting charged particles move across the chamber and get counted as charges.
• What is radioactive decay?

  When an unstable nucleus becomes more stable over time by emitting ionising radiation.
• What is half-life?

  the time it takes for half of the unstable nuclei in a sample to decay or for the activity of the sample to halve or for the count rate to halve.
• One Becquerel is equal to one nuclear decay per second.
• Exposing objects to beams of radiation is called irradiation
• Irradiation from radioactive decay can damage living cells
• Irradiation from radioactive decay can damage living cells
• The process of irradiation does not cause the object to become radioactive.
• They use gamma rays to kill cancerous tumours. These beams are aimed at the tumour from many different directions to maximise the dose on the tumour but to minimise the dose on the surrounding soft tissue.
• Using radiation to kill cancer can damage heathy tissue
• To make sure irradiation doesn't cause any long term effects, scientists consider:

  -the nature of decay

  -the half life

  -toxicity
• Advantages of irradiation:

  • sterilisation can be done without high temperatures
  • it can be used to kill bacteria on things that would melt
• Disadvantages

  • it may not kill all bacteria on an object
  • it can be very harmful - standing in the environment where objects are being treated by irradiation could expose people’s cells to damage and mutation
• Contamination occurs if an object has a radioactive material introduced into it. 
• Injected radioactive sources can be used as tracers to make soft tissues, such as blood vessels or the kidneys.
• When contaminating resources, this is done safely by choosing isotopes that:

  -have very short half lives

  -are not poisonous
• When using a Geiger-Miller tube, the isotopes used must:

  -emit gamma rays

  -half a half life of at least several days (to allow emissions to build up)

  -not be poisionous
• fill in gaps

  A) tracers

  B) short

  C) limited

  D) surgical

  E) isotopes

  F) radioisotope

  G) cells

  
• fill in guepepas

  A) outside

  B) in

  C) radioactive

  D) radioactive

  E) shielding

  F) blocked

  G) removed

  
•  Nuclear radiation can ionise chemicals within a body, which changes the way the cells behave. It can also deposit large amounts of energy into the body, which can damage or destroy cells completely.
• GAPAPAPS

  A) cancer

  B) DNA

  C) irradiate

  D) mutations

  E) cancer

  F) blood

  
• Being exposed to highly radioactive materials or being exposed to radioactive materials for long periods of time or on a regular basis increases the dose received which, in turn, increases the risk.
• Radioactive materials occur naturally and, as a result, everyone is exposed to a low-level of radiation every day. 
• Background radiation affects everyone mainly by irradiation, but a small amount is from being contaminated by radioisotopes in the food and drink that is consumed.
• • a beta particle has a lot of energy but may not cause a lot of damage because of its low ionisation power
• • an alpha particle will have less energy but will cause more damage in a shorter distance because it is bigger
• Can electromagnetic radiation affect the electron arrangement of an atom?

  Yes
• alpha particles are used in smoke detectors because they have a small range in air so will be stopped by a thin sheet of material, meaning the alpha radiation cannot escape the smoke detector
• When it asks about detecting radioactivity:

  • The isotope travels along the pipe, if there is no leak, the radiation wont escape the pipe.
  • If there is a leak, the isotope escapes the pipe and more radiation can reach the detector, which causes the count rate to increase
  • An increase in count rate indicates the leak
  • The isotope could be gamma OR beta emitting
  • gamma can escape the pipe and reach the detector
  • beta would be blocked by the pipe but not by the ground