KEY TERMS Flashcards
Define an isotope
Different versions of an element (nucleus) with the same number of protons, but different number of neutrons
Define a half life
A half life is the time taken for half of an atom to decay
Define Nuclear Fission
the process where the nucleus of an atom splits into two or more smaller nuclei and other particles
Define Nuclear fusion
the process by which two light atomic nuclei combine to form a single heavier one while releasing massive amounts of energy
Describe a Fission reaction
A –> A + B
Describe a Fusion reaction
A + B –> A
Parts of a radiation badge
Plastic casing, photographic film, aluminium, lead
Use of plastic casing
To protect sensitive detection materials from low - energy radiation and for high radiation to penetrate and be measured.
Use of photographic film
The photographic film will darken when exposed to radiation, recording all radiation that touches the film.
Use of aluminium
1mm of aluminium will allow for gamma and beta particles through, and block alpha radiation. Alpha cannot penetrate through this material, beta particles are able to penetrate through 1mm of aluminium but is stopped at a few milimeters.
Use of lead
The use of lead shielding will remove both alpha and beta particles as they are both not strong enough to penetrate through, however will allow gamma to penetrate through. (Thicker lead shielding will NOT allow gamma to pass through)
State the two conservation laws that are obeyed by nuclear reactions
- Nucleon number (atomic mass) is conserved in a nuclear reaction
- The charge is conserved in a nuclear reaction
Explain what the term ionisation means
Ionisation is the process by which an atom or molecule gains / loses electrons, resulting in the formation of charged particles (ions)
Why do nuclear power stations use fission to generate electricity?
Nuclear power stations generate electricity by using nuclear fission, where splitting atoms releases heat, which is then used to boil water, create steam, and turn turbines connected to generators, producing electricity
Outline the two different methods of ionisation
Direct, and Indirect
Direct ionisation
Involves electrostatic forces between the radiation and the atom’s electrons. This requires the radiation to be charged, and therefore can only occur with alpha and beta particles
Indirect ionisation
Involves providing the electron with enough energy to leave the atom, relating to gamma rays as they have high energy, this energy can be passed on to electrons. Energising the electrons allows them to move further away from the nucleus.
Which type of ionisation has more effect on matter
Direct ionisation has more effect on matter than indirect ionisation
Describe a dosimeter and outline its purpose
A device that detects the type of radiation the wearer is exposed to. It uses photographic film that darkens when exposed to radiation.
Why does a dosimeter have different windows
They are used to differentiate between the types of radiation, as different types of radiation have different penetration abilities
