Using Radioactive Materials Flashcards
What is half life
The time taken for half the radioactive atoms to decay
The time radioactivity takes to reach half its dose
What is half life measured in
Bq(becquerel)- activity
Sv - Dose
What is radioactive decay
It is random and it is when the atoms decay into a new atom
What is background radiation
Low level radiation that’s around all of the time it comes from radioactivity of unstable isotopes which are all around us
Radiation from space which is known as cosmic rays the atmosphere protests us from this
What causes the level of background radiation to to change due to location
Some underground rocks can cause higher levels of background radiation at the surface Especially if they release radioactive radon gas
So the amount of radon gas that is in people’s houses depends on where they live
How do household fire alarms use alpha
A weak source of Alpha can be placed in a smoke detector close to two electrodes the source causes ionisation and a current flows if there is a fire the smoke will absorb the radiation stopping the current and the alarm sounds
How does gamma sterilise things
Gamma rays kill all microbes this means that the food won’t go off as quickly
It doesn’t involve high temperatures so fresh fruit or plastic items can be sterilised in this way
The source needs to be strong and have long half life so it doesn’t need replacing too much
How is radiation used in tracers and thickness gauges
Some radioactive isotopes can be put I to the patients body then a computer uses a detector to produce an image of the flow
Only beta and gamma can be used so that the radiation passes out of the body and they should have a short half life
Gamma tracers can be used in the same way in underground pipes
How are gamma rays used to treat cancer
High doses of gamma rays kill all living cells so they will kill cancer cells the radiographer have to be careful to direct the gamma rays at only the cancer to not harm healthy cells
What was radium used fir before people knew it was radioactive
Medicine and everyday products like luminous watches
What does ionising radiation do to our body
Low doses kill cells and cause mutations which cause cancer
High doses give people radiation sickness and kill the cells completely
Outside the body beta and gamma are most dangerous because they can get into our body and alpha can’t but inside the body alpha is most dangerous because once we put it in it can’t get out again where as beta and gamma just pass straight out
How should you protect yourself from radiation in a lab
Never allow skin to contact with the source always use tongs
Keep the source as far away from the body as possible
Keep the source pointing away from the body and never look directly at it
Always put the source back in the labelled lead box
How should you protect yourself when working near a nuclear reactor
Wear full protective suits to stop any radioactive particles getting stuck on the body
Lead lined suits or lead barriers and screens can stop people coming into contact with gamma rays
Workers use remote control robot arms
What is bad about radioactive waste
They can’t be recycled
They are radioactive for very long times Because they have very long half lives
They are very dangerous for humans
How is nuclear waste dealt with now
Vitrification
They melt the waste materials to form a glass then it is stored in containers deep under ground
It can also just be put into thick metal containers then put in a deep hole and buried with concrete
