Lecture Notes on Nuclear Physics and Radiation

Structure of the Atom

• Nucleus: Central part made of protons and neutrons (nucleons)
  • Protons: Positive charge (+1)
  • Neutrons: No charge (0)
  • Mass of protons and neutrons are similar
• Electrons: Orbit around the nucleus
  • Negative charge (-1)
  • Mass is 1,800 times smaller than protons

Atomic Structure

• Electrically Neutral Atom: Equal number of protons and electrons
• Element Identification: Number of protons defines the element

Nucleid Notation

• Symbol (X): Chemical symbol for the element
• Mass Number (A): Total number of protons and neutrons
• Atomic Number (Z): Number of protons
• Example: Lithium with 3 protons, usually 3 electrons, and mass number 7

Isotopes

• Atoms of the same element with different numbers of neutrons
• Examples:
  • Hydrogen: Protium, Deuterium, Tritium
  • Carbon: Carbon-12, Carbon-13, Carbon-14
• Stability: Isotopes can be stable or unstable (radioactive)

Background Radiation

• Sources: Natural (rocks, soil, air, etc.) and artificial (medical equipment)
• Types of Radiation: Alpha particles, beta particles, gamma rays

Ionizing Radiation

• Causes atoms to gain or lose charges, forming ions
• Detected using a Geiger-Müller tube

Types of Nuclear Emission

• Alpha Particles:
  • Heavy, positive charge (+2), low speed
  • Stopped by paper or skin
• Beta Particles:
  • High-speed electrons, negative charge (-1)
  • Stopped by aluminum
• Gamma Rays:
  • Electromagnetic waves, no charge
  • High penetration, stopped by lead

Radioactive Decay

• Process: Random and spontaneous
• Decay Types:
  • Alpha Decay: Emission of an alpha particle
  • Beta Decay: Neutron turns into a proton, emitting a beta particle
  • Gamma Decay: Emission of gamma rays, reducing energy

Half-Life

• Time for half of a radioactive sample to decay
• Measurement: Activity measured in becquerels

Uses of Radiation

• Smoke Detectors: Use alpha particles
• Material Thickness Measurement: Uses beta radiation
• Medical Diagnosis: Gamma rays for tracing
• Cancer Treatment: Gamma rays for radiotherapy

Effects and Safety of Ionizing Radiation

• Can damage or kill cells, cause mutations
• Safety Precautions:
  • Use protective gear, limit exposure time
  • Store radioactive materials safely

Nuclear Fission

• Process: Splitting of a large nucleus into smaller nuclei
• Example: Uranium fission
• Nuclear Reactor: Controlled fission reaction to generate energy

Nuclear Fusion

• Process: Combining of light nuclei to form a heavier nucleus
• Example: Fusion in stars (e.g., Sun)
• Challenges: Requires high temperature and pressure

Conclusion

• Understanding of nuclear physics and radiation is crucial for various applications in energy, medicine, and industry.
• Precautions are necessary to safely utilize the benefits of radiation.
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