Background Radiation - Radiation that exists around us all the time
Sources -
Ionising nuclear radiation is measured using a detector connected to a counter [ONLY IONIZING — gamma cant be]
Counter Rate - Number of decays per second recorded by a detector and recorded by the counter — Counts/Second or Counts/Minute - Measured through GM tube
Count rate decreases with distance since radiation spreads out more
Corrected count rate = Readings - Background radiation
Some atomic nuclei are unstable due to an imbalance in forces within particles in nucleus
Radioactive decay = Process of emitting radiation, it is random and spontaneous
| Particle | What is it | Ionization | Penetration | Atomic Changes |
|---|---|---|---|---|
| Alpha | 2 protons + 2 neutrons [helium nuclei] | Highly - creates dense trail of ions | Few cm air | |
| Few mm thick paper | Mass += -4 | |||
| A num += -2 | ||||
| Beta - | Electron [neutron in atom becomes proton and electron] | Weakly - creates less dense trail of ions | Thin aluminum sheets | |
| Thick clothing | Mass same | |||
| A num += 1 | ||||
| Gamma | Electromagnetic Wave | Not Ionizing - Not a particle | Lead or concrete | Nothing |
Ionization is dependent on kinetic energy and charge -