Of the five main types of radiation, three types of radiation are of special concern related to our health. The three of main concern are Alpha, Beta and Gamma radiation.
- The alpha rays are helium nuclei
- The beta rays are electrons
- The gamma rays are photons having high energy
What is Radiation
Radiation is everywhere. It has been around since the creation of the earth. It can be found in rocks, soil, water, plants and sometimes in the sky.
Radiation has a broad spectrum of meaning. It can be electromagnetic waves or subatomic particles or both. Some forms of radiation produce emissions of ionizing energy. These are neutrons, photons, and high energy charged particles like gamma rays.
There are different sources of radiation. Natural sources include cosmic radiation from space, terrestrial radiation emitted from radioactive elements in the ground. There is also man-make radiation released by the detonation of an atomic bombs.
Radiation emitting materials mined from the earth are used in health care, power generation, consumer products and industry.
Because of of its wide spread use, there is increased potential for unwanted human exposure.
Sometimes unwanted exposure comes from technological advancements. Now that aircraft can travel higher in the atmosphere, there are radiation exposure risks that do not affect those of us with our feet on the ground. Then there is always the risk of radioactive fall out from the occasional super power flexing their atomic strong arms.
Some people are exposed to radiation event though they do not work with or near radioactive materials. One job with high radiation exposure is firefighting. The concern is with the three types of radiation of the five that are most dangerous.
Five Types of Radiation
- X Radiation
- Neutron radiation
At the end of the 19th century Thomson and Rutheford studied the phenomenon of the ionisation of gases illuminated with the rays discovered by Becquerel. During the experiment Rutheford discovered that there were two kinds of such radiation: The first one called the alpha rays was easily absorbed even by paper; the second one called the beta rays could penetrate through even thick metal brasses like for example 0.25 centimetres of aluminium. Soon the third kind of radiation was discovered. It had high penetrating power – it could go through even a couple of centimetres thick layers of lead. This third kind of radiation was called the gamma rays.
In the few next years scientists spent explaining the nature and properties of those three kinds of radiation.
The alpha rays (having low penetrating power) consist of positively charged particles – in a magnetic field, and in an electric field alpha rays are deflected in the same direction as other positively charged particles. It turned out that the ratio q/m (charge to mass) of the alpha particles is two times smaller than q/m of hydrogen nuclei. Scientists concluded that alpha particles are helium nuclei whose mass equals 4*(hydrogen mass), and whose positive charge equals 2*e. As you know the helium nucleus consists of two protons and two neutrons.
The beta particles (having much higher penetrating power) can be deflected in a magnetic field, and in an electric field, and the deflection direction shows that they are charged negatively. In the further study it turned out that they are simply electrons.