P6.2 Flashcards
what is radioactive contamination
the presence of unwanted radioactive nuclei on other materials
what is irradiation
the process of exposing a material to nuclear radiation
the material does not become radioactive
give 3 practical applications of radioactive materials
medical tracers
radiotherapy
smoke alarms
how do smoke alarms work
alpha radiation is emitted into the air, reaching a detector and completing the circuit. If smoke is present, it blocks alpha radiation so it does not reach the detector and the circuit is broken, causing an alarm to sound
what kind of radiation is used in smoke alarms
alpha
Give a use of beta emitters
thickness monitoring of paper
why are isotopes with long half-lives particularly harmful
they remain radioactive for much longer periods of time
they must be stored in specific ways to avoid humans and the environment from being exposed to radiation for too long
what kind of radiation is used for radiotherapy
gamma
how does thickness monitoring work
a source and receiver are placed on either side of the sheet. If there is a drop or rise in the number of particles detected, the thickness has changed and needs adjusting
state 2 uses of nuclear radiation in the field of medicine
examining of internal organs
controlling and destroying unwanted tissue
how is radiation used in sterilisation
gamma emitters are used to kill bacteria/parasites on equipment
what is nuclear fusion?
the joining of two light nuclei to produce a heavier nuclei and release energy
explain the process of radiotherapy
gamma emitters direct gamma rays onto specific areas with cancerous cells.
the cells absorb the radiation and die
what are the risks of ionising radiation to people
it can damage living cells, causing them to die or mutate and become cancerous
name two isotopes of hydrogen which are commonly used in nuclear fusion
deuterium and tritium
which releases more energy, nuclear fission or nuclear fusion
nuclear fusion
explain the difficulty of generating energy through nuclear fusion
fusion requires very high temperatures which in itself requires large quantities of energy and also requires casing which can withstand them
alongside two smaller nuclei, what else is emitted in a fission reaction
two or three neutrons
gamma rays
energy
what can mass be converted into
energy
what is nuclear fission
the splitting of large, unstable nuclei to form smaller more stable nuclei (+the emission of spare neutrons)
what usually needs to happen to induce fission
the unstable nuclei must absorb a neutron
spontaneous fission ( where no neutron absorption occurs) is rare
what takes place during a chain reaction in a nuclear reactor
an unstable nucleus absorbs a neutron
the nucleus undergoes fission and releases 2 or 3 further neutrons.
these induce more fission, which results in a chain reaction.
