Radioactivity vs Radiation
Radioactivity is the spontaneous nuclear transformation that results in the formation of new elements. In other words, radioactivity is the capability to release radiation. There are a large number of radioactive elements. In a normal atom, the nucleus is stable. However, in the nuclei of radioactive elements, there is an imbalance of neutrons to protons ratio; thus, they are not stable. To become stable, these nuclei will emit particles, and this process is known as radioactive decay. Each radioactive element has a rate of decaying, which is known as its half life. Half life tells the time needed to a radioactive element to decrease to one half of its original quantity. The resulted transformations can be Alpha particle emission, Beta particle emission and orbital electron capture. Alpha particles are emitted from a nucleus of an atom when the neutron to proton ratio is too low. For example: Th-228 is a radioactive element which can emit alpha particles with different energies. When a beta particle is emitted, a neutron inside a nucleus is converted to a proton by emitting a beta particle. P-32, H-3, C-14 are pure beta emitters. Radioactivity is measured by the units, Becquerel or Curie.
Radiation is the process where waves or energy particles (e.g.: Gamma rays, x-rays, photons) travel through a medium or space. The unstable nuclei of radioactive elements are trying to become stable by emitting radiation. Radiation can be either ionizing or non-ionizing. Ionizing radiation has high energy, and when it collides with another atom, it will be ionized, emitting another particle (e.g. an electron) or photons. The emitted photon or particle is radiation. The initial radiation will continue to ionize other materials until all its energy is used up. Alpha emission, beta emission, X-rays, gamma rays are ionizing radiations. Alpha particles have positive charge, and they are similar to the nucleus of a He atom. They can travel across a very short distance (i.e. few centimeters). Beta particles are similar to electrons in size and charge. They can travel a longer distance than alpha particles. Gamma and x-rays are photons, not particles. Gamma rays are produced inside a nucleus, and x-rays are produced in an electron shell of an atom.
Non ionizing radiations do not emit particles from other materials, because their energy is lower. However, they carry enough energy to excite electrons from ground level to higher levels. They are electromagnetic radiation; thus, have electric and magnetic field components parallel to each other and to the wave propagation direction. Ultra violet, infra red, visible light, microwave are some of the examples to non ionizing radiation. We can protect ourselves from harmful radiation by shielding. The type of shielding is determined by the energy of the radiation.
Radioactivity Vs Radiation
- Radioactivity is the process by which certain elements release radiation.
- Radiation is energy or energetic particles which are released by radioactive elements.
- Measured radioactivity is given by Becquerel or Curie, but it doesn’t say anything about the energy of the radiation.