Types of radiation
Radiation is defined as the emission or transmission of energy in the form of waves or particles. It exists all around us. We, as humans, emit radiation due to the potassium in our muscles, bananas have potassium too. The sun and cosmic rays produce radiation, underground deposits of ores such as uranium and thorium but also masonry do so too, brazil nuts have a thousand times the average concentracion of every other organic product. Radiation has no smell or taste. In a general area, it is measured by a geiger counter, while a dosimeter can meausre the dosage one might receive. Radiation is divided into two types: ionizing and non-ionizing. Ionizing radiation has enough energy to ionize atoms and molecules by taking away electrons, and thus poses danger to living beings. Non-ionizing radiation does not have enough energy to ionize atoms and molecules, meaning that it is generally safe.
The electromagnetic spectrum is the depiction of electromagnetic radiation organised by wavelength or frequency. Electromagnetic radiation is defined as a self-propagating wave in an electromagnetic field carrying momentum and energy through space. Most often, that is how radiation is portrayed. In this post, I will give more information on the types of radiation in the spectrum, as well as on other kinds of radiation.
Types of radiation on the electromagnetic spectrum:
Radiowaves: They are a type of electromagnetic radiation. They have the lowest frequencies (below 300 gigahertz/GHz) and longest wavelengths (bigger than a millimeter), as can be seen above. In a vacuum, they travel at the speed of light but in Earth their speed is slightly lower. Naturally, radiowaves are emitted by lightning as well as astronomical objects such as stars, nebulas and galaxies, and are part of the blackbody radiation (thermal electromagnetic radiation emitted by something which is in thermodynamic equilibrium with the rest of its environment). Artificially, they are created by a transmitter connected to an antenna, creating radiowaves which another antenna connected to a radio receiver receives and processes the signal. Most commonly, radiowaves are used in radio communication, broadcasting, radar systems, navigation systems, satellites, and wireless computer networks. As radiowaves are non-ionizing radiation, they cannot cause damage to humans. One of their uses medically is to induce heat for increased blood flow and recently to kill cancer cells, as radiowaves can be penetrate objects and deposit their energy in them.
They are divided to the exact types depending on their frequency:
Terahertz waves/T-waves/THF (Tremendously High Frequency): 0.1-10 terahertz/THz
EHF (Extremely High Frequency): 30-300 gigahertz/GHz
SHF (Super High Frequency): 3-30 GHz
UHF (Ultra High Frequency): 300 megahertz/MHz - 3GHz
VHF (Very High Frequency): 30-300 MHz
HF (High Frequency): 3-30MHz
MF (Medium frequency): 300 kilohertz/kHz - 3 MHz
LF (Low Frequency): 30-300 kHz
VLF (Very Low Frequency): 3-30 kHz
ULF (Ultra Low Frequency): 300 hertz/Hz - 3kHz
SLF (Super Low Frequency): 30-300Hz
ELF (Extremely Low Frequency): 3-30Hz
Microwaves: Electromagnetic radiation whose wavelengths (a meter to millimeter) are shorter than radiowaves but longer than infrared waves, with frequencies ranging from 300MHz to 300GHz. The prefix micro denotes that the microwaves have shorter wavelengths than radiowaves. Microwaves are non-ionising radiation and so they pose no danger to humans. If injury does occur, it is caused by exposure to the eyes, which can result in cataracts. To other areas, extreme exposure can cause serious burns. The frequencies of microwaves are included below and in the format of name: frequency range, wavelength range, common uses.
L band: 1-2GHz, 15-30 cm, mobile phones, amateur radio, GPS.
S band: 2-4GHz, 7.5-15 cm, weather radar, some satellites, amateur radio, Bluetooth, mobile phones, microwave ovens.
C band:4-8 GHz, 3.75-7.5cm, amateur radio, long distance radio communication.
X band: 8-12 GHz, 25-37.5 mm, satellite communications, radar, amateur radio, space communications.
Ku band: 12-18 GHz, 16.7-25mm, satellite communications, molecular rotational spectroscopy.
K band: 18-26.5 GHz, 11.3-16.7mm, radar, astronomical observations, automotive radar, molecular rotational spectroscopy.
Ka band: 26.5-40 GHz, 5-11.3 mm, satellite communications, molecular rotational spectroscopy.
Q band: 33-50GHz, 6-9 mm, satellite communications, radio astronomy, automotive radar, molecular rotational spectroscopy.
U band: 40-60 GHz, 5-7.5mm, I can't find any uses.
V band: 50-75 GHz, 4-6mm, scientific research.
W band: 75-110GHz, 2.7-4mm, satellite communications, automotive radar, military radar targeting and tracking applications.
F band: 90-140GHz, 2.1-3.3mm, radio astronomy, modern radars, communications satellites, amateur radio.
D band: 110-170GHz, 1.8-2.7mm, radio astronomy, amateur radio, directed energy weapon.
Infrared: Has longer wavelengths (380THz-300GHz) than visible light but shorter than microwaves. It is used for night vision devices, for astronomy to penetrate dusty regions in space, infrared thermal-imaging cameras assist medically, in firefighting, and for the detection of overheating electrical components, surveillance, environmental monitoring, short-range wireless communication, and weather forecasting. Subdivisions of infrared are mentioned below in the format of name: wavelength, frequency, uses.
Near Infrared/NIR: 0.75-1 μm (micrometer), 214-400 THz, night vision devices, near infrared spectroscopy.
Short-Wavelength Infrared/SWIR: 1.4-3 μm, 100-214 THz, long distance telecommunications.
Mid-Wavelength Infrared/MWIR: 3-8μm, 37-100 THz, guided missile technology.
Long-Wavelength Infrared/LWIR: 8-15μm, 20-37 THz, can be detected by sensors when the temperature of something is above room temperature.
Far Infrared/FIR: 15-1000μm, 0.3-20THz, lasers.
Visible Light: The part of the electromagnetic spectrum visible to the human eye. The wavelength is between 380-750nm (nanometers) and the frequency is between 400-790THz. It does not include all visible colors as many are combinations of various wavelengths. The spectral colors (colors that can be produced by a single wavelength or frequency) as well as their wavelengths and frequencies are mentioned below.
Red: 625-750nm, 400-480THz.
Orange: 590-625nm, 480-510THz.
Yellow: 565-590nm, 510-530THz.
Green: 500-565nm, 530-600THz.
Cyan: 485-500nm, 600-620THz.
Blue: 450-485nm, 620-670THz.
Violet: 380-450nm, 670-790THz.
Ultraviolet: Has a wavelength shorter of visible light but longer than x-rays, so between 100-400nm. Some kinds of it are considered ionizing radiation. Ultraviolet is produced by the sun, electric arcs, mercury vapor lamps, tanning lamps, black lights, and Cherenkov radiation (the blue glow appearing when a nuclear reactor is underwater). Humans need ultraviolet radiation to produce Vitamin D and it also used to treat skin conditions such as psoriasis, eczema, jaundice and others. Extreme exposure can result in eye problems, sunburns, skin cancer, and aggravation of skin conditions. The types are described below, names, wavelengths, and extra information.
Ultraviolet A/UVA/Long-wave UV: 315-400nm. Used mainly for insect electrocution traps (350-370nm). It is not absorbed by the ozone layer.
Near Ultraviolet/NUV: 300-400nm. Birds, insects, and fish can see it.
Middle Ultraviolet/MUV: 200-300nm.
Ultraviolet B/UVB/Medium-wave UV: 280-315nm.
Ultraviolet C/UVC/Short-wave UV: 100-280nm. Can be ionizing at shorter wavelengths.
Far-UVC: 200-235nm. Used for disinfection and poses very little risk.
Far Ultraviolet/FUV: 122-200nm. Is ionizing at shorter wavelengths.
Hydrogen Lyman-alpha/H Lymen-α: 121-122nm. It is the spectral line of hydrogen, meaning that it has a strong absorption when in the atmosphere of earth.
Extreme Ultraviolet/EUV: 10-121nm. Entirely ionising radiation.
Vacuum Ultraviolet/VUV: 10-200nm. Absorbed strongly by oxygen and higher wavelengths can propagate through nitrogen.
Uses for ultraviolet radiation include insect electrocutor traps (359-370nm), curing of polymers and printer inks (300-365nm), light therapy (300-320nm), medical imaging of cells (280-400nm), analysis of protein, discovery of drugs and sequencing of DNA (270-360nm), forensic analysis and drug detection (200-400nm), disinfection and decontamination (240-280nm), optical sensors (230-400nm), barcodes and label tracking (230-365nm), photoionization and ultraviolet photoelectron spectroscopy (30-200nm), and extreme ultraviolet lithography (13.5nm).
X-rays: Have high energy, a wavelength shorter than ultraviolet rays, longer than those of gamma rays -and thus 10nm-10 pm/picometers, and the x in the name denotes an unknown type of radiation. Their frequency ranges from 30PHz (petahertz) to 30EHz (exahertz). They are ionizing radiation and can lead to ARS. Due to their discovery by Wilhelm Röntgen, x-rays take his name in many languages. Pregnant women are not allowed to do x-rays due to the danger to the fetus or her own reproduction organs.
X-rays are divided into three types: soft x-rays (photon energies below 5-10keV/electronvolt, are easily absorbed in air), hard x-rays (photon energies above 5-10keV, are used for medical radiography and airport security), and HEX-rays (High-Energy x-rays, photon energies of 80-1000keV, used in cancer therapy).
Gamma rays: Electromagnetic radiation emitted by radioactive decay, laboratory sources, or astronomical events such as solar flares, pulsars, and gamma-ray bursts. Their photon energy ranges from 104 eV to 107 eV. They are used to alter semi-precious stones, to measure levels, density and thickness for chemicals, food, soaps, detergents, for the measurement to fluid levels in oil and water, for sterilization and removal of bacteria, and for diagnostic properties in nuclear medicine. Extreme exposure to gamma rays can result in cancer as well as ARS, being the main way of irradiation to criticality victims.
Gamma rays are divided into very-high-energy (photon energies ranging from 100GeV/gigaelectronvolt to 100TeV/teraelectronvolt, emitted by astronomical sources) and ultra-high-energy (with photon energies above 100TeV which reveal the source of cosmic rays)
Other types of radiation:
Other kinds of radiation not in the electromagnetic spectrum include neutrons, alpha particles and beta particles.
Neutrons: Subatomic particles found in the nuclei of atoms alongside protons. They have no charge. Neutrons are essential for nuclear power, as during fission, they are released and trigger other fissions, and also for nuclear weapons and cancer treatments. Indirectly, they can cause ionizing radiation. Damage to the human body is caused by disruption to the body's molecules and atoms. Some of them do exist naturally.
Alpha particles: Comprised of two protons and two neutrons bound together, and are usually produced during alpha decay. Their kinetic energy is 5MeV. Alpha particles cannot penetrate the skin very deep but pose extreme danger if ingested, and can cause ARS. They are used in smoke detectors, radioisotope thermoelectric generators for space probes, static eliminators, and cancer treatment.
Beta particles: A high energy and speed electron produced by radioactive decay. They are less ionizing than alpha particles. They produce the blue glow of Cherenkov radiation in underwater reactors. They are used in the treatment of eye and bone cancer as well as used as tracers in various medical tests, but also test the quality of items such as paper, since their thickness can be determined by how much radiation the product will receive. The element that produces the most beta particles is strontium-90. Beta particles can cause mutations in DNA and ARS if enough get into the body.
Delta ray: Secondary electrons with enough energy to escape from the primary radiation source and produce further ionization. This term is most often used in high energy physics to describe electrons in particle accelerators.
Epsilon ray: Rays composed by electrons. It is not used today except in very specific circumstances.
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