Types of Radiation

Radiation can be defined as that energy which comes from a source and passes through some material or space. Whether we realize it or not, we are constantly surrounded by all kinds of radiations. Radiation is not only emitted during cancer radiation therapy, but also from microwaves, cell phones, computers and so on. Radioactive substances are seen to give out radiations for years together.

Where does radiation come from?

Radiation is produced when unstable elements lose their energy in order to become stable. For example, uranium and radium are the most unstable of all elements and emit the most radiation. Radiation is a type of energy that occurs naturally and can even be man made. When the radiation is from the Sun or outer space, then it is called cosmic radiation, and when it comes from minerals in the Earth it is called terrestrial radiation. 13% of all radiation present is man made. Break up being - 12% is produced by X-ray and MRI machines, and the remaining 1% is produced by nuclear industries. Man-made radiation is more harmful as compared to natural ones due to the fact that it is more concentrated.

Types of Radiation

There are many types of radiation present which vary in intensity and form. Depending on the type of radiation, it is seen to travel in the form of waves or particles. The primary types of radiations are Alpha radiation, Beta radiation and Gamma radiation.

Characteristics of Alpha Radiations:

• Alpha radiations are seen only in heavier elements, that is in elements with atomic number greater than 52.
• The Alpha particle is a Helium nucleus consisting of two neutrons and two protons, weighing 8000 times that of an electron with a double electric charge.
• They are positively charged particles emitted by the radioactive decay of unstable atoms.
• These particles get easily ionized, therefore are quickly stopped from entering into any material.
• Alpha radiations do not penetrate into the skin, thus even if unshielded skin comes in contact with alpha radiation, no damage is done.
• Alpha emitting particles if inhaled, absorbed (through wounds and bruises) or swallowed can prove dangerous to the human body.
• Alpha particles travel a short distance (few centimeters) through air and through solid substances - only a hundredth of a mm.
• Several instruments have been designed specifically to measure alpha radiations. However, since alpha radiations do not penetrate, the instruments fail to measure them through even fine layers of blood, water, dust, etc.

Characteristics of Beta Radiations:

• Beta radiations consist of fast moving, either positively or negatively charged electrons and have a mass as small as 1/2000th the mass of a neutron irrespective of the charge.
• The negatively charged beta particle is called negatron and the positively charged beta particle is called positron.
• Unlike alpha radiations (helium nucleus), these beta radiations are electrons and thus lighter. Therefore, beta radiations can penetrate deeper into air as well as materials such as plastic, water and so on.
• Even though beta particles travel faster than alpha particles and can penetrate with greater intensity, the beta radiations can easily be stopped using an aluminum sheet.
• Since beta particles have higher penetration power, they can penetrate into the germinal layer (where new cells are formed) of the skin and cause harm.
• Beta-emitting particles if inhaled or consumed will cause a lot of damage.
• Most of the beta radiations can be measured by using survey instruments such as the CD V-700. However, in cases of Carbon 14, Sulfur-35 and Tritium, the amount of beta radiation emitted is so low in energy and low penetrating power, that it is difficult to detect or measure it.

Characteristics of Gamma Radiations:

• Gamma radiations are electromagnetic radiations just like visible light, ultraviolet rays and radio waves.
• These radiations are the most energetic of all electromagnetic radiations, with a wavelength as short as 1/10th of a nanometer.
• Gamma radiations have high penetrating power and can travel many centimeters through the air and materials.
• Gamma radiations are very harmful to human beings (as they penetrate many centimeters into the human tissue) and cause great harm through external as well as internal contact.
• These radiations mostly accompany alpha and beta emissions.
• Dense materials (denser than clothing and turn-out gear) are required to work as a shield from gamma radiations.
• Low levels of gamma radiations can be detected and measured with the help of a Geiger counter, such as the CD V-700. On the other hand, high levels can be measured with the help of an ionization chamber (CD V-715).

Radiations that are produced by microwaves, televisions, etc. are not high enough to cause harm. However, exposure to small amounts of radiation for long periods of time increases the risk of getting cancer. Since radiation is carcinogenic, it can provoke or lead to cancer. High doses of radiation can cause reddening of the skin, nausea, and injury. Very high doses of radiation can even lead to death. Therefore, one must make sure that the time spent in the vicinity of radioactive substances is limited.