4.2.5 Beta Decay

• Beta Decay


  A type of radioactive decay where an unstable atomic nucleus transforms into a more stable one by emitting a beta particle
• Beta decay changes the original nucleus into a different element
• Types of Beta Decay

  • Beta-Minus (β⁻)
  • Beta-Plus (β⁺)
• Beta-Minus (β⁻) Decay

  A neutron is converted into a proton, an electron (beta-minus particle), and an antineutrino
• Beta-Plus (β⁺) Decay

  A proton is converted into a neutron, a positron (beta-plus particle), and a neutrino
• Properties of Beta Particles

  • Beta-Minus Particle
  • Beta-Plus Particle
  • Penetration Power
  • Ionizing Power
• Beta-Minus Particle

  Charge: -1 (electron), Mass: Approximately 1/1836 of a proton
• Beta-Plus Particle

  Charge: +1 (positron), Mass: Same as beta-minus particle
• Penetration Power

  Beta particles have a moderate penetration power, able to pass through several millimeters of plastic or aluminum
• Ionizing Power

  Beta particles have lower ionizing power compared to alpha particles but higher than gamma rays
• Effects of Beta Decay

  • Nuclear Change
  • Energy Considerations
• Beta-Minus Decay Effect

  Increases the atomic number by 1, creating a new element
• Beta-Plus Decay Effect

  Decreases the atomic number by 1, creating a new element
• Beta decay releases energy in the form of kinetic energy carried away by the emitted beta particle and the accompanying neutrino or antineutrino
• Beta-Minus Decay Example

  • Carbon-14 Decay: _{6}^{14}C \rightarrow _{7}^{14}N + \beta^- + \bar{\nu}_e
• Beta-Plus Decay Example

  • Positron Emission Tomography (PET) Scan
• Applications of Beta Decay


  • Medical Imaging
  • Radiotherapy
• Medical Imaging

  Beta-plus decay is used in PET scans to visualize metabolic processes in the body
• Radiotherapy

  Beta particles are used to treat certain types of cancer by targeting tumor cells
• Biological Effects of Beta Particles

  • Can cause damage to tissues if they penetrate the body
  • Less harmful than alpha particles if the source is outside the body
  • Can cause ionization and potentially damage DNA if internalized