Electromagnetic radiation is the means by which energy transportation reaches the universe through wave motion. Electromagnetic wave travels in a direction that is at right angles to the vibrations of the perpendicularly oscillating electric and magnetic field vectors.
Figure 1, Illustrating electromagnetic radiation propagation.
Ionizing radiation is the radiation which has sufficient energy such that during mutual interaction with an atom, it can dislodge tightly held electrons from the fields of an atom thereby causing the atom to be charged or ionized. Ionizing energy can either be in wave form or particle form.
Electromagnetic Radiation has the following properties; it can travel through vacuum or empty space, the general speed of light does not vary space, the wavelength of light is described by the distance between successive crests or between troughs. When travelling through medium, the electromagnetic radiation interacts with other materials that can change its direction through refraction and reflection while the intensity may be reduced by absorption (Ohanian, 1995). The radiation can also be diffracted as it travels through narrow aperture.
Figure 2, Illustrating absorption and emission of electromagnetic radiation by a particle
Particulate ionizing radiation is composed of atomic or particles like electrons and protons which carry kinetic energy or energy in the form mass in motion that can remove electrons from an atom (Haken "Wolf, 1996).
Figure 3, illustrating how energy moves in particulate radiation.
Electromagnetic Ionizing, Cosmic Rays, X-Rays, Gamma Rays, and Ultraviolet Rays
Cosmic rays are high-energy particles that get in the Earth from sources found outside the Earth. Most of the cosmic rays are the nuclei of atoms that varies from the lightest elements to the heaviest elements within the periodic table Cosmic rays have the following properties; Energy is 4 x 10^7eV, Frequency is 10^22Hz and Wavelength of 10^-14m. Cosmic rays are believed to be ejected from the explosion of stars within the space.
Gamma rays originate due to the interactions of cosmic rays and they offer the best ideal means to study cosmic rays in and near their sources. Gamma rays have the following properties Energy is 4 x10^6eV, Frequency is 10^21Hz and Wavelength is 10^-13m
X-Ray is the mostly applied rays of the ionizing radiation. It is used in; chest X-rays radiography machine, and X-ray scanners and many other applications. X-Ray has the following properties; Energy is 4 x 10^3eV, Frequency is 10^18Hz and Wavelength of 10^-10m.
Ultraviolet (UV) radiation is found in sunlight composing about 10% of the total solar light output. It has the following properties; Energy is 4 x10^0 eV, Frequency is 10^15 Hz and Wavelength is 10^-7m.
Electromagnetic Non-Ionizing; Visible Light, Radiofrequencies (MRI, Ultrasound) Microwaves
Non-ionising radiation is a general term for electromagnetic, static electric and magnetic fields with frequencies varying from 0 to 300 GHz. Non-ionizing radiation (NIR) thus comprises all radiation and fields of the electromagnetic spectrum that have no sufficient energy to produce ionization on matter.
The visible light falls with the spectrum electromagnetic spectrum that is visible to the human eye. The visible wavelengths range from approximately 400 to 800 nm with the longest visible wavelength being red while the shortest is violet. It is the visible light that enables us to see.
Radiofrequencies have the frequency range from 10^4 to 10^11.5 and it has applications in; microwaves appliances, television sets signals, FM and AM radio frequencies, and short waves that is used in dielectric and induction heaters.
Microwave radiation is also another nonionizing electromagnetic radiation with a frequency between 300 MHz and 300 GHz. Microwaves can be used in cooking foods in microwave ovens since it can cause water and fat molecules to vibrate. They are also being used in transmitter chip and antenna of mobile phones.
Particulate Alpha and Beta Particles
Alpha and Betta are two of the three examples of particles of radiations. Radioactivity occurs as a result of unstable atomic nuclei that spontaneously decay to form nuclei that have a higher stability as a result of release of energetic sub-atomic particle (Haken " Wolf, 1996). Here, the fission is triggered by the bombardment of energy neutrons in unstable isotopes. The instability of atoms is as a result of unequal nuclear forces in their nuclei.
Alpha Particles are emitted by a proton with high mass and a highly unstable nucleus such as a helium atom (Institute of Physics, 2018). Alpha particles are thus helium nucleus with two protons and two neutrons with no electrons. Lack of electrons within Helium means that the two positively charged protons cannot be balanced. Alpha particles are thus particles that are positively charged that moves at greater speeds due to instability (Haken " Wolf, 1996).
Beta Particles are emitted by neutrons which are highly unstable and they are usually high energy electrons. These electrons of Beta particles are generated when a neutron within the nucleus divides to make a proton with a resultant electron. Beta particles are negatively charged.
Alpha and beta particles are regarded as directly ionizing since they possess charge and can thus associate with the atomic electrons through coulomb forces.
Source of Radiation (Natural Background vs. Man-Made)
Radiation has two sources which is either natural background radiation source or man-made source of radiation.
Natural Background source includes cosmic radiation, terrestrial radiation and internal radiation.
i).Cosmic radiation occurs due to the interaction of the Earth and all its contents. An example is the charged particles from the sun or stars that act with the Earth’s atmosphere and magnetic fields to produce beta and gamma radiations. Cosmic radiation within the Earth varies due to variation in Earth’s magnetic field and Earth’s elevation.
ii).Terrestrial radiation occurs as a result of radioactive materials within the soil, water and vegetation. Low levels of uranium and thorium or their decaying components can be consumed with food or water whereas elements like radon can get in the body inhalation.
iii). Internal radiation is found in everybody from birth and they include; radioactive potassium, carbon, lead and other isotopes. The internal radiation dose varies from person to person. Some reports show that an average annual dose of internal radiation in human is approximately 40 millirems per year (UNSCEAR, 2008).
Man-Made radiations sources are as a result of processes made by man that can produce radiation when someone regularly comes into contact with it. Examples are; granite countertops/fiestaware, nuclear power, or terrorism and disaster.
i).Granite Countertops/Fiestaware- Items made from granite for human use has traces of uranium. Some types of vintage red glazed pottery (fiestware) also contain radioactive elements since their bright red colour is obtained by the use of uranium.
ii).Nuclear Power Plants that involves the use of fission reaction in uranium to convert water to steam which in return run rotary giant engine generators. It is argued that the yearly average dose from a nuclear power plant to an individual is approximately equal to the amount internally generated by the natural decay of natural radioactive element found in the human body (Mirion Technologies, n.d.).
iii).Terrorism/Disaster or War-Modern world has advanced the war level to the use of atomic weapons such as the case of Hiroshima-Nagasaki airstrike and the Chernobyl explosion of 1986. Such explosions and air strikes have considerably contributed to the continental amount of the atmospheric radioactive material that are associated with human health complications (UNSCEAR, 2008)
Somatic Effect vs. Genetic Effect
Somatic effects are radiation effects that occur within the individual due to radiation exposure. The somatic effects attack the somatic cells through biological, chemical and physical agents of ionization radiation Somatic effects include; radiation burns, acute radiation syndrome, radiation induced heart complications, and radiation induced cancer.
Genetic effects on the other hand occur as a result of human exposure to the ionization radiation which can destroy the genetic materials within the reproductive cells and can bring about mutations that are hereditary and can be passed through generations (Shapiro, 2002). Genetic effects thus affect the offspring.
Genetic effects are generally sub-grouped in three types such as;
i). Severe development disorders- Examples include; still birth, malformation, and early postnatal death. These effects are also found within other animals like insects and fishes. The severe development effects are caused as a result of genomic, chromosol and essential gene mutations with predominant dangerous effects.
ii). High level risk of cancer- This demonstrates itself by high occurrences of spontaneous tumours and higher sensitivity to carcinogenic agents.
iii).Decease in physical fitness-This effect is generally associated by negative health effects and like increased cancer risk, it is as a result of instability and functional failure of in the genome cells within the progeny of parents that were exposed to radiation.
References
Haken, K. and Wolf, H.C.(1996).The Physics of Atoms and Quanta: An Introduction to Experiments and Theory (5th edn), Springer, Berlin.
Institute of Physics.(2018). Nature of ionising radiations. Retrieved on Oct. 8, 2018 from http://practicalphysics.org/nature-ionising-radiations.html
Mirion Technologies,(n.d.). Man-made sources of radiation. Retrieved on Oct. 8, 2018 from https://www.mirion.com/introduction-to-radiation-safety/man-made-sources-of-radiation/
Ohanian H.C. (1995). Modern Physics (2nd edn), Prentice-Hall International Inc., New Jersey.
Shapiro, J., (2002). Radiation Protection. 4th ed., Harvard University Press.
UNSCEAR,(2008). Sources and effects of ionization radiation: Exposure of the public and workers from various sources of radiation, Vol.1 ISBN 978-92-1142274-0 Retrieved on Oct. 8, 2018 http://www.unscear.org/docs/reports/2008/09-86753_Report_2008_Annex_B.pdf
