Radiation Flashcards
Tracers
To monitor the functions of parts of the body
Application of radioactive in medicine
Tracers
Gamma emitters
Gamma rays
Gamma emitters
Swallowed to follow the tracer
Gamma rays
Focused beams used to kill cancer cells
Application of radioactive in sterilisation
To kill off microorganisms and bacteria on surgical equipment and on foodstuff
Radioactive dating
Measuring proportion of C-14 can tell us how long that material has been dead
Radioactive decay
Random process
As the decay process proceeds, the rate of decay decreases
Due to the more stable nuclei
Background radiation
Earth’s rocks
Cosmic rays
Medical
Nuclear power/ weapons
Earth’s rocks
Decay of isotopes of uranium, produces radon and thoron gases
Cosmic rays
Stars explode and shower the earth in cosmic rays
Medical
Radioactive materials are used in medical treatment
Nuclear power/ weapons
The testing of these sometimes leaks from nuclear power stations
Detective ionising radiation
Photographic film
Geiger-muller tube
Photographic film
Becomes fogged when exposed to ionising radiation
Worn as a badge
Geiger-Muller tube
Ionising radiation ionises the gases within the tube
A pulse of current is passed between electrodes
This is fed into a rate metre
Atomic mass
Protons + neutrons in nucleus
Atomic number
Protons in nucleus
Protons =electrons
Alpha charge
+2
Alpha construction
Helium nuclei
2 neutrons, 2 protons
Alpha range
Short
Alpha ionising
Heavily ionising
Alpha stopped by
Thin card
Beta charge
-1
Beta construction
Fast moving electrons
Beta ionising
Less ionising
Beta travelling distance
Long distances
Beta stopped by
Thin aluminium
Gamma charge
0
Gamma construction
Photons of high energy EM waves
Electromagnetic wave
Gamma rays penetrative power
Extremely
Gamma ionisation
Interact with other atoms which can then emit ionising radiation
Gamma stopped by
Thick lead
Nuclear fission
Uranium-235 is fissile (can be easily split)
How nuclear fission works
U-235 is struck by a low energy neutron
U-235 breaks apart and releases energy in the form of kinetic and gamma ray photons
Parent nucleus (U-235) produces two daughter nuclei + many neutrons
A chain reaction could start
Hazards of radioactivity
Ionising radiation can kill living cells
Can mutate cells (malfunction/reproduce uncontrollably)
Highly radioactive material with long- half lives
Require land, lead and concrete to be stored for many hundreds of years
Geiger and marsden
A beam of alpha particles was fired at a gold leaf
A zinc sulphide screen was used as a detector
Outcomes of G&M
Most alpha particles passed through
Some deflected as they passed through (alpha and gold positive)
Some bounced back
Conclusion of G&M
Atom is mainly empty space
The positive charge is only in a small area
Nucleus is a lot smaller than the atom
What effected the G&M
Effected by speed of alpha particles, nuclear charge, distance of alpha to nucleus
