Wednesday, 23 October 2013
During nuclear decay, three different types of radiation are given off: alpha, beta and gamma. They all have different ionizing abilities as well as different speeds and energies.
Alpha radiation is given off from the decay of heavier atoms. The alpha particle is made up of two protons and two neutrons. This radiation has the lowest penetration power out of the three types. This is because it can be stopped by a few centimetres of air. For this reason, alpha decay is not regarded as very dangerous as it can be stopped so easily and cannot penetrate human skin. However, if it is inhaled or ingested, it is the most lethal type of radiation. This is because it is the most ionizing out of all the radiation. This means that if it comes in to contact with living cells, it can cause them to mutate, which can lead to conditions such as radiation poisoning. They also have many uses. Smoke detectors rely on alpha radiation to function. They pass alpha radiation between two charge plates. Because the alpha radiation ionises the air, charge can pass from one plate to the other. However, if there is too much smoke, the air cannot transmit as much charge and the drop is detected by the device and the alarm goes off. Alpha radiation is also used in small scale generators, such as those used in pacemakers, as they can produce a lot of heat for their size over a long period.
Beta radiation is a high speed electron that is emitted during nuclear decay. This radiation had the medium ionising ability and the medium speed. It can travel close to the speed of light and can slightly ionize cells. It can be stopped by a thin sheet of aluminum and is therefore not too dangerous either. It is mainly used industrially when it can be used to measure the thickness of the material that is being produced. For example in paper mills and aluminum foil production, there is often an alpha emitter above or below the output sheets. There is then a beta radiation detector on the other side of the output sheets. If there is a high reading, the rollers adjust to thicken the sheets, if there is a low reading, the rollers adjust to thin the sheets.
Gamma radiation is the most high energy radiation produced. It is an electromagnetic wave. Being such, it travels at 300,000,000 metres per second. It is almost entirely stopped by a few metres of lead or cement. It is the least ionising of all the of the type of radiation but still poses a considerable threat as it is hard to stop. There are many uses for gamma radiation. One of the main uses is medical sterilization. Medical equipment is irradiated with gamma rays, which kills off any living cells left on them. It is also used to detect broken pipes.
One of the three types of natural radioactivity is gamma radiation. The other two types are in the form of particles but gamma radiation is in the form of waves. Natural production of this radiation takes place due to gamma decay, which is a term used to describe the natural decay in the high-energy states of an atomic nucleus.
There are also artificial means by which the gamma rays are produced in the lab. These methods include induced fission, fusion, neutral pion decay and the annihilation of electron and positron. Whether naturally produced or artificially, gamma radiation is an ionizing radiation and therefore it is biologically hazardous.
Ionizing radiation has the inherent capability to liberate electron from any atom or molecule. Thus when exposed to ionizing radiation, the molecules in the cells of the body start liberating electrons which makes them abnormal and in turn the health of the individual gets affected. Thus, gamma rays have a negative effect on the health of humans and other creatures. Alpha and beta particles are the other types of ionizing radiation.
Any kind of radiation is a part of the spectrum of electromagnetic radiation. There are different types of electromagnetic radiation and they are classified based on the frequency of the individual waves. The gamma radiation is classified as the one, which has the highest frequency of them all. This high frequency possessed by the gamma rays makes them highly energetic, capable of liberating electrons from the atoms and molecules. This is the reason why the gamma rays are also classified under ionizing radiation.
Another property of the gamma radiation is that it loses its energy very slowly. This property imparts two different characteristics to the gamma rays. First is the ability to travel large distances in air. Gamma rays can travel tens to even hundreds of meters in the air, which depends totally on the energy they were carrying at the beginning of the journey. The other characteristic is the ability to penetrate through thick plates of solid material, even metal.
Because of having the highest frequency among all the types of electromagnetic radiation, the gamma rays are high-energy waves. This enables them to penetrate deep in the metal plates and even come out from the other side if the thickness is less. Therefore, the shielding done in order to protect individuals from gamma radiation is very thick and made of extremely dense materials such as lead.
Gamma radiation is utilized for industrial as well as scientific purposes. In the industry, gamma rays are used to induce molecular changes in precious and semi-precious stones. For example, gamma rays are used to convert white topaz into blue topaz.
Wherever there is the need to measure levels, density, thickness etc. in the industries like refining, soaps, detergents, mining, food and chemical, it is done by using non-contact industrial sensors. These sensors operate on the sources of the gamma radiation. Other applications include medical treatments of humans and for medical diagnostic purposes.