Radiation Flashcards
Half-life?
Time it takes for the activity to fall by half
How does pipeline leak cheching work?
A radioactive source producing gamma rays is put into the pipe. Someone walks above the pipe with a geirger-muller tube if it is detected there is a leak
Industrical uses of radiation
Pipeline leak checking,controling the thickness of sheet materials, smoke detectors
medical uses of radiation
sterilising equitment,radio therapy, radioactive tracers
Effects of inionising radiation on living tissue
kills the cells in the living tissue
how to calculate half life from numerical data
find how many half lifes have happend- draw arrow until have required value
how to calculate half life from a graph
find intail value number on graph, half of intial value number of graph , then half-first
experiment to measure the half life of a radioactive material
measure the activity then later measure again, find the half life
structre of an atom
proton-positve-nuclues
neutron-nutral-nucleus
electron-negative-orbitaing
why are some atoms radioactive
have an ustable nucli and too much energy
how do atoms become stable
by emmiting radiation(Particles or electromagnic waves)
ionistaion
when an atom gains or loses an electron
ion
an atom that has lost or gained an electron
three types of inonising radiation
Alpha,beta,gamma rays
alpha radiation
made up of alpha particles which consits of two nutrons and protons (helium nuclues),most inoning,stopped by paper or skin, range of a few cm
beta radiation
made up of high energy electrons,middle ionising,stopped byy few cm of aluiminim or body tissue, range of a few meters
gamma ray radiation
maade up of high energy electromgaitic waves,least inoinsing,stopped by several cm of lead or meter of concreate,long range
background radiation
background radation is mainly natral radiation that is consantly around us
natural sources of background radiation
randon gas from the ground,buildings and the ground,cosmic rays,food and drink
aritifical sources of background radiation
nucllear power and wepons testing, medical
experiment to measure background radiation
connect a geiger-muller tube to an electronic counter, count for 60secs note down how many repeat 3 more times, find the background raiation then do average count divided by 60secs
what is activity
number of distergrations per second
unit for activity
bequerels (Bq)
formula for activity
a=n/t
How do smoke detectors work?
Contains a mild radioactive source.
Emminted radiation causes ionisation in nearby particles.
So current flows in circut.
When smoke enters radiation is abosrbed so circut breaks. Alarm then sounds
How does serilisation work
instruments are exposed to high intensity gamma ray source then kill all living material on it
How does controlling the thickness or material work
Radiation is emmited above the sheet and deteced below if the thickness increase, radiation decreases
How does radio therapy work
Treatment for some cancers require intense radiation that kills the cancer cells but healthy cells also damaged
how does radioactive tracers work
A radioactive liquid is injected into the patient doctors that can detect the radiation and check everthing is working how it should be.
