Properties or Characteristics of Alpha Particles
1. Alpha particles are 24He nuclei with 2 units of positive charge and mass of 4 amu.
2. Because they are charged particles so they can be deflected by electric and magnetic fields.
3. They ionize the medium through which they pass. Their ionizing power is much higher than β- and γ-rays.
4. Because of the high-ionizing power, they can be easily absorbed by few centimeters of air or fraction of millimeter thick aluminum.
5. Naturally occurring a-emitters emit a-particles with energy in the range of 5 MeV to 10 MeV.
6. Alpha particles when fall on certain materials like ZnS, barium platinocyanide, etc. emit flashes of light called scintillations. This property of scintillation was initially used to detect a-particles.
7. Long exposures to a-emitters produce harmful effects on the human body.
Properties or Characteristics of Beta Particles
1. Beta particles are charged particles, either negatively charged (β-) or positively charged (β+), depending on whether they are electrons or positrons, respectively.
2. Beta particles have a much smaller mass compared to alpha particles. Electrons have a mass of approximately 9.11 × 10-31 kilograms, while positrons have the same mass but with a positive charge.
3. Beta particles can travel at high speeds, often close to the speed of light, especially in cases of beta particles emitted from highly radioactive isotopes.
4. Beta particles are moderately penetrating. They can penetrate through materials like paper or thin aluminum foil but can be stopped by thicker materials such as wood, plastic, or several millimeters of aluminum.
5. Beta particles ionize atoms they interact with by knocking off electrons. However, their ability to ionize is less than that of alpha particles due to their smaller mass.
6. Beta particles are deflected in a magnetic field, and the direction and degree of deflection depend on their charge and velocity, according to the Lorentz force law.
7. Beta particles interact with matter through electromagnetic interactions (Coulomb forces), which cause them to lose energy as they pass through material. This leads to a gradual decrease in their velocity and penetration power.
8. Beta particles are produced during the decay of certain radioactive isotopes, such as carbon-14 (14C), potassium-40 (40K), and strontium-90 (90Sr).
9. Beta particles can be detected using various methods, including Geiger-Müller counters, scintillation detectors, and cloud chambers, which exploit the ionizing properties of these particles to produce measurable signals.
Properties or Characteristics of Gamma Rays
1. Gamma rays are electromagnetic waves just like X-rays or visible light.
2. They always travel with velocity of light irrespective the energy of γ-rays.
3. They do not cause any appreciable ionization and are not deflected by electric or magnetic fields.
4. Gamma-rays have high penetrating power, much larger than that of α- or β-particles.
5. They have frequencies greater than 1019 Hz and wavelengths shorter than 10 picometers (pm).
6. They have no charge or mass.
7. Gamma rays can be detected using specialized instruments such as gamma-ray spectrometers and scintillation detectors.