Types of radioactive decay (alpha, beta, gamma)

Types of Radioactive Decay

Radioactive decay is the process by which an unstable nucleus loses energy by emitting radiation. The three main types of radioactive decay are:

1. Alpha Decay

1. In alpha decay, an unstable nucleus emits an alpha particle, which consists of 2 protons and 2 neutrons (a helium nucleus).
2. The mass number decreases by 4 and the atomic number decreases by 2.
3. Alpha particles have low penetration power and can be stopped by paper or human skin.
4. Common in heavy elements like uranium and radium.
5. Example: Uranium-238 → Thorium-234 + Alpha Particle.

2. Beta Decay

1. In beta decay, a neutron in the nucleus converts into a proton and emits a beta particle (electron or positron).
2. There are two types: Beta-minus (β⁻) and Beta-plus (β⁺).
3. In β⁻ decay, an electron and an antineutrino are emitted.
4. In β⁺ decay, a positron and a neutrino are emitted.
5. The mass number remains the same, but the atomic number increases (β⁻) or decreases (β⁺) by 1.
6. Beta particles have moderate penetration power and can be stopped by aluminum foil.
7. Example: Carbon-14 → Nitrogen-14 + Beta Particle (β⁻).

3. Gamma Decay

1. In gamma decay, the nucleus releases excess energy in the form of gamma rays (high-energy electromagnetic waves).
2. There is no change in the mass number or atomic number.
3. Gamma rays have high penetration power and can pass through several centimeters of lead or meters of concrete.
4. Often accompanies alpha or beta decay to release the remaining energy.
5. Example: Cobalt-60 → Nickel-60 + Gamma Radiation.

Key Characteristics of Radioactive Decay

1. Radioactive decay is a random and spontaneous process.
2. It follows the principle of half-life, the time taken for half of the radioactive nuclei to decay.
3. The activity of a radioactive substance is measured in becquerels (Bq) or curies (Ci).
4. Radioactive decay is used in dating techniques (e.g., Carbon-14 dating).

Applications

1. Alpha decay is used in smoke detectors.
2. Beta decay is applied in medical imaging and treatment (e.g., PET scans).
3. Gamma radiation is used in cancer therapy and sterilization of medical equipment.
4. Radioactive isotopes are used in nuclear power plants and scientific research.