ionising radiation

• ionising radiation


  radiation with enough energy that to remove tightly bound electrons from the orbit of an atom, causing that atom to become charged or ionised
• types of ionising radiation

  alpha (α), beta (β), gamma (γ)
• alpha particles are...


  helium nuclei, consisting of two neutrons and two protons
• alpha particle

  
• alpha particle charge


  +2
• alpha particle mass


  4 amu
• alpha radiation


  radiation that is made up of alpha particles that are emitted from the nucleus of an atom
• alpha particle penentration


  do not penetrate very far into materials and are stopped quickly, they can only travel a few centimetres in air and are absorbed by a sheet of paper
• alpha particle energy


  very ionising
• alpha radiation uses


  smoke detectors

  - it ionises air particles, causing a current to flow. if there is smoke in the air, it binds to the ions, meaning the current stops and the alarm sounds
• alpha decay ... the charge and mass of the nucleus


  decreases

  - this is because it has a positive charge of +2 and has a mass of 4
• what happens to an atom when it undergoes alpha decay?

  atomic number decreases by 2 (loses two protons)

  mass number decreases by 4 (loses 2 protons and 2 neutrons)
• beta particles are...


  high-speed electrons
• beta particle

  
• beta particle charge


  -1
• beta particle mass


  0 amu
• beta radiation


  radiation that is made up of beta particles that are emitted from the nucleus of an atom
• how are beta particles made?

  when a neutron in the nucleus splits into a proton and electron in attempts to stabilise the nucleus
• beta particle penetration


  penetrate moderately far into materials before colliding and have a range in air of a few metres - that can be absorbed by a sheet on aluminium (5mm thick)
• beta particle energy


  moderately ionising
• beta radiation uses


  beta emitters are used to test the thickness of sheets of metal, as the particles are nit immediately absorbed by the material like alpha radiation would be and do not penetrate as far as gamma rays. therefore, slight variations in thickness affect the amount of radiation passing through the sheet
• beta decay ... the charge of the nucleus

  increases

  - this is because it has a negative charge of -1 and does not have mass
• what happens to an atom when it undergoes beta decay?

  atomic number increases by 1 (gains a proton)

  mass number does not change
• gamma rays are...


  electromagnetic waves with a short wavelength
• gamma ray

  
• gamma ray charge


  0
• gamma ray mass


  0 amu
• gamma radiation


  radiation that is electromagnetic waves emitted from the nucleus of an atom
• gamma ray penetration


  penetrate far into materials without being stopped and will travel a long distance through air, absorbed by thick sheets of lead or lots of metres of concrete
• gamma ray energy


  weakly ionising
• gamma ray uses


  cancer treatment and sterilising food and medical equipment
• gamma rays don't change the ... of the nucleus

  charge or mass

  - this is because they are just a way of getting rid of excess energy from the nucleus: it has no charge or mass
• what happens to an atom when it undergoes gamma decay?

  atomic number does not change

  mass number does not change
• Geiger-Müller tube


  used for the detection of gamma radiation, X-rays, and alpha and beta particles
• how does the Geiger-Müller tube work?

  the tube briefly conducts electrical charge when high energy particles or gamma radiation make the gas conductive by ionization
• which type of ionising radiation is the most hazardous outside of the body?

  gamma, because it can penetrate the skin and damage the cells inside
• which type of ionising radiation is the most hazardous inside of the body?

  alpha, because they are highly ionising and do not have the skin protecting internal cells from damage
• which metal is used for containers that store radioactive sources?

  lead, because its high density does not allow any radiation to penetrate it
• decay


  the random process by which an unstable atomic nucleus loses energy by radiation and changes into a different type of atom
• radiation uses

  - sterilize equipment

  - molecular tagging/tracking

  - diagnosing disease

  - cause/treatment for cancer

  - decrease pain