Radioactive Decay and Nuclear Radiation

• some atomic nuclei are unstable
• the nucleus gives out radiation as it changes to become more stable. this is a random process called radioactive decay
• activity is the rate wt which a source os unstable nuclei decays
• activity is measured in bequeral bq
• count-are is the number or decays recorded each second be a detector
• nuclear radiation emitted may be:

  • an alpha particle - this consists of two neutrons and two protons, the same as a helium nucleus
  • a beta particle - a high speed electron ejected from the nucleus as the neutron turns into a proton
  • a gamma ray - electromagnetic radiation from the nucleus
  • a neutron