Ionising radiation Flashcards
Natural sources of radiation
cosmic radiation, animals, rocks, buildings, soil, plants
Artificial sources of radiation
X-ray machines, nuclear power, nuclear missiles, nuclear weapons testing
physical characteristics of ionising radiation
penetrating, invisible to the eye, reduces in intensity, can cause biological effects
half-value layer
thickness of a substance which will transmit one 1/2 of the intensity of the radiation incident upon it
the thicker the material is, the less photons will be passed through
half-life
time taken for half the atoms to decay
inverse square law
total amount of radiation in the beam doesn’t change, but the concentration decreases with increasing distance from the source
3 factors of radiation safety
time, distance and shielding
time
radiation dose can be reduced by limiting exposure time
distance
amount of radiation exposure depends on the distance from the source of the radiation
shielding
shielding, such as lead aprons should be used if the radiation source is too intensive
lead equivalent
the thickness of lead would absorb the same amount of radiation as the given material
radon gas
radioactive, colourless, tasteless gas which is formed by small amounts of uranium
banana dose equivalent
informal way of comparing doses of ionising radiation to the dose received by eating a single banana of average size.
useful concept to help explain relative radiation risk to the public
alpha decay
process which an unstable atomic nucleus loses energy by emitting radiation.
consists of two protons and two neutrons tightly bound together (most ionising and destructive form of ionising radiation)
beta decay
unstable atomic nucleus loses energy by emitting radiation
spontaneous emission of a fast moving particle with the mass of an electron from a nucleus
negative and positive beta particles are produced by the decay