radioactivity Flashcards
What do you use to measure radioactivity
Geiger muller tube
what does an alpha particle consist of
2 protons
2 neutrons
4
2
What is a beta particle
An electron which is ejected from the nucleus at a very high speed
A beta particle is formed inside the nucleus when a neutron changes into a proton and electron
0
-1
What are gamma radiation
a type of electromagnetic radiation from the nucleus
Discuss alpha particles range in air
Alpha particles are large. They can travel around 5cm in air before they collide with a or particles and stop
Discuss beta particles range in air
They can reach 15cm in air before stopping.
Discuss gamma radiation range in air
Travels several metres in air before stopping
Discuss alpha particles penetrating power
Alpha particles are relatively easy to stop, stopped by a single sheet of paper
Discuss beta particles penetrating power
They are stopped by a few mm of aluminium
Discuss gamma radiation penetrating power
Stopped by several cm of lead
Discuss the order of ionisation with radioactive sources
Alpha particles: Very strongly ionising
Beta particles: quite strongly ionising
Gamma radiation: weakly ionising
What happens in gamma decay to the atomic and mass number
They are not changed at all
Can scientists predict when a nucleus will decay
no decay is a random process
What is half life
The time it takes for the number of nuclei of the isotope in a sample to halve
What are risks of radiation
Can increase the risk of cancer in humans
people have got to take precautions like sheilding like a lead apron or lead walls
What is irradiation
Exposing an object to nuclear radiation( beta alpha gamma and neutron) , we use this in sterilisation.
The object doesn’t become radioactive because it only comes in contact with the radiation and not the radioactive source
What is radioactive contamination
When unwanted radioactive isotopes end up on other materials, this is called contamination
This is hazardous as the radioactive atoms decay and emit ionising radiation
What are the dangers of different radioactive contamination
Alpha: stopped by dead skin cells, damaging if inhaled or swallowed
beta: can penetrate the skin into the body
gamma: can penetrate the body but likely to pass straight through
What are sources of background radiation
Natural sources:
rocks are radioactive
cosmic rays from space
man made sources:
fall out from nuclear weapon testing
nuclear accidents
Your exposure to background radiation can be affected by what
your location (cornwall)
your occupation (flight crew)
What is the dose of radiation measured in
sieverts (Sv)
What are key factors to consider when using a tracer
The tracer must emit radiation that can pass out of the body (beta and gamma)
The tracer must not be strongly ionising to minimise damage to body tissues
Tracer must not decay into another radioactive isotope
short half life
What are medical uses of radiation
radiotherapy to destroy tumours
tracers to detect issues in the body
What is the process of tracers
The tracer is injected, swallowed or placed into the blood
a gamma detector is used to monitor the radiation
The pattern of the radiation shows where the substance goes
used to detect organ functions, leaks or blockages.
