About Radiation.
Radiation is the energy that travels through space or matter in the form of particle or wave. It involves transfer of energy from one place to another. It can also be seen as a form of energy given off by matter in the form of rays or high speed particle. Radiations are either photons or particles. Imagine a shaft of yellow sunlight beaming through a window. According to quantum physics that beam is made of zillions of tiny packets of light, called photons, streaming through the air.
There are two types of radiation:
A. Ionising radiation.
B. Ionising radiation.
A.Non – Ionising radiation;- Non-ionising radiation (cannot ionise matter): such as visible light, signals from mobile phones and radio waves, others includes:
— Acoustic radiation force.
— Infrared.
— Light.
— Starlight.
— Sunlight.
— Microwave.
— Radio waves.
— Ultraviolet.
B. Ionising radiation:- ionising radiation (cannot ionise matter), such as radiation emissions from uranium ore and high frequency waves in the electromagnetic spectrum (eg X-
rays), others includes:
— Radioactive decay.
— Cluster decay.
— Background radiation.
— Alpha particle.
— Beta particle.
— Gamma ray.
— Cosmic ray.
— Neutron radiation.
— Nuclear fission.
— Nuclear fusion.
— Nuclear reactors.
— Nuclear weapons.
— Particle accelerators.
— Radioactive materials.
Ionizing radiation can either be directly ionsing or indirectly ionizing.
a) Directly ionizing radiation (charged particles) electron, proton, alpha particle, heavy ion.
b) Indirectly ionizing radiation (neutral particles) photon (x ray, gamma ray), neutron.
Each type of ionising radiation is capable of disrupting stable atoms and causing them to have an imbalance of charge (ionisation). This can cause chemical changes in living matter which may cause harm to people’s health, depending on the radiation dose received. There are three main types of ionising radiation: alpha (a), beta (b) and gamma (c). Alpha and beta radiations are particles, while gamma radiation is a wave similar to X-rays. These forms of radiation differ in their ability to penetrate into the body or other materials and also in their ability to cause harm to people.
Alpha particles:- As they are relatively big, heavy and slow, alpha particles are not able to penetrate very far through materials. They are stopped by a few centimetres of air or a sheet of paper and even by the dead layer of skin on the outside of our bodies. As they usually cannot penetrate into the body, alpha particles do not pose a significant hazard from outside the body. However, radioactive materials emitting alpha particles can get into the body by inhalation, ingestion or through open wounds. They can then damage tissue and have a greater potential to cause cancer than beta particles and gamma rays.
Beta particles: These are relatively light, small and fast, so they may travel several metres in air and can penetrate through exposed skin. Consequently, beta particles can present a hazard from inside or outside the body. They can be stopped by thin sheets of aluminium or perspex.
Gamma rays: These rays have no weight and can penetrate through the body, depositing some of their energy on the way and so causing harm. Gamma rays are therefore a hazard both inside and outside the body. They can be stopped or exposure can be reduced by the use of thick, heavy shielding.