# data[].attributes.body
Radiation is often a misunderstood concept. Whether you've first heard of the concept of radiation from sci-fi stories or military weaponry, radiation does not always involve nuclear fallouts and nuclear reactor disasters.

Briefly, radiation is defined as the emission or transmission of energy in the form of waves or particles through space or through a medium. Examples of radiation include:

Electromagnetic radiation, the flow of photons through matter or a vacuum

Acoustic radiation, the rippling of matter, some of which we perceive as audible sound

Gravitational radiation, the rippling of spacetime, the "fabric" of gravity

Colloquially, when the term "radiation" is used, it is often just a shorter way of "electromagnetic radiation," even though this isn't the true definition of the word. Consequently, you often see acoustic or gravitational radiation referred to by acoustic or gravitational waves instead.

So for now, let's focus on just the electromagnetic radiation kind.

Electromagnetic radiation is fundamental to the universe and our daily lives, whether it is from the x-ray machines we use to diagnose medical conditions or the light we see every day, including the blue light from our electronics.

# data[].attributes.headline
Modes of Radioactivity: Alpha, Beta, and Gamma.

# data[].attributes.subject
Modes of Radioactivity: Alpha, Beta, and Gamma.

# data[].attributes.body
Click here to view this text with formatted equations.

Many nuclei decompose by emitting particles and in doing so, become a different nucleus. This is what is known as radioactivity, more precisely, radioactive decay, governed by the weak nuclear force, one of the four fundamental forces of the universe.

In chemistry, we learned that atoms were unable to change into different elements. This is because in chemical reactions discussed, only the electrons were changing. In radioactive decay, the nucleus itself, which contains the protons that dictate which element an atom is alongside neutrons which dictate what isotope the element is, is changing. All nuclei with 84 or more protons are radioactive by default. Even nuclei that have less than 84 protons have radioactive, unstable isotopic variants. In fact, any element can go through nuclear changes and turn into different elements.

In radioactive decay, three common emissions occur:

alpha particles, denoted with alpha (α)

beta particles, denoted with beta (β)

gamma rays, denoted with gamma (γ)

As you may notice, these particles were named using the first three letters of the Greek alphabet. This is because scientists were unable to identify them when they were first observed. A while later, these particles were identified. Alpha particles are helium-4 nuclei, beta particles are electrons, and gamma rays are photons.

Alpha Decay

The radioactive decay process that emits alpha particles is called alpha decay. An example of a nucleus that undergoes alpha decay is uranium-238. The alpha decay of uranium-238 is:

238_92 U -> 4_2 He + 234_90 Th

In this nuclear change, the uranium atom "transmutes" into an atom of thorium. In the process, it gave off an alpha particle. Let's look at the symbol for the alpha particle:

4_2 He

The bottom number in a nuclear symbol is the number of protons. That means that the alpha particle has two protons in it that were lost by the uranium atom. The two protons also have a positive charge of 2. The top number, 4, is the mass number or the total of the protons and neutrons in the particle. Because it has two protons, and a total of four protons and neutrons, alpha particles must also have two neutrons. Alpha particles always have this same composition: two protons and two neutrons.

Beta Decay

Another common radioactive decay process is beta decay, which emits beta particles. A beta particle is simply just a high energy electron that is emitted from the nucleus.

It may not make much sense at first, because nuclei do not contain electrons, yet during beta decay, an electron is emitted from the nucleus. At the same time that the electron is being emitted from the nucleus, a neutron is turning into a proton. You may picture this as a neutron breaking into two pieces with the pieces being a proton and an electron, however, this is not what actually happens.

For convenience, though, we will treat beta decay as a neutron splitting into a proton and an electron. The proton stays in the nucleus, increasing the atomic number of the atom by one. The electron is ejected from the nucleus and is the particle of radiation called beta.

To include an electron into a nuclear equation, an atomic number and a mass number had to be assigned to an electron in order to balance the equation. The mass number assigned to an electron is 0, which is reasonable, since the mass number is the number of protons plus the number of neutrons, and an electron contains neither protons nor neutrons. The atomic number assigned to an electron is -1, because that allows a nuclear equation containing an electron to balance atomic numbers. Therefore, the nuclear symbol representing an electron is:

0_(-1) e

It can also be represented in terms of the letter beta:

0_(-1) β

Thorium-234 is a nucleus that undergoes beta decay. Here is the nuclear equation for this beta decay:

234_90 Th -> 0_(-1) e + 234_91 Pa

Gamma Rays

Gamma ray production is often a side effect of nuclear reactions of all types. In the alpha decay of uranium-238 shown above, two gamma rays of different energies are emitted in addition to the alpha particle.

238_92 U -> 4_2 He + 234_90 Th + 2 0_0 γ

Virtually all of the nuclear reactions, but they are often omitted for simplicity. Nuclear reactions exert much more energy than chemical reactions. Chemical reactions release the difference between the chemical bond energy of the reactants and products. Nuclear reactions release some of the binding energy and may convert tiny amounts of matter into energy. That means that nuclear changes involve almost one million times more energy per atom than chemical changes!

# data[].attributes.headline
How are these radioactive decays detected?

# data[].attributes.subject
How are these radioactive decays detected?

# data[].attributes.body
A common universal radiation detection device is the Geiger-Muller (GM) tube. The ionizing effects of radiation is used in the GM tube as a means of detecting the radiation.

The GM tube consists of a hollow cylinder filled with a gas at low pressure, with a thin window made of mica at one end, and central electrode inside the GM tube. As shown in the image, a high voltage supply is connected across the casing of the tube and the central electrode.

When alpha, beta or gamma radiation enters the tube, it produces ions in the gas. The ions created in the gas enable the tube to conduct electricity. A current is then produced in the tube for a short time, in which the current produces a voltage pulse. Each voltage pulse corresponds to one ionizing pulse of radiation entering the GM tube. The voltage pulse is then amplified and counted. The greater the level of radiation, the more ionization in the tube, so the greater the number of counts.

However, these counts may still not provide a completely accurate reading, as the number of counts could simply keep increasing, so GM tubes are commonly used for just detecting any presence of radiation, or providing estimates.

# data[].attributes.body
Carbon dating, also known as radiocarbon dating or carbon-14 dating, is one of the most important tools in modern archeology. It allows archeologists to assess historic samples on their date of creation, providing more precision on dates rather than relying visual inspection. Carbon dating works by examining the properties of objects which contain organic material by taking advantage of the special properties of carbon-14, a radioactive carbon isotope. This isotope is unique, because carbon isotopes are usually not radioactive. As this carbon isotope is part of the carbon cycle that every organisms undergoes, a sample with organic materials can be dated.

Carbon-14 is constantly being created in the Earth's atmosphere by the interaction of cosmic rays with nitrogen in our atmosphere. The resulting carbon-14 reacts with oxygen in our atmosphere to form a radioactive carbon dioxide, which ends up in photosynthetic animals through respiration, which other organisms can then get as part of the food chain. When this organism, it stops exchanging carbon with its environment, so the amount of carbon-14 it contains begins to decrease as it begins to undergo radioactive decay.

Measuring the proportions of carbon-14 in a sample from a piece of organic, once-live material, such as a piece of wood or a fragment of bone, provides information that can be used to calculate when the animal or plant died. The older a sample is, the higher the proportion. Because carbon-14’s half-life, which is the time it takes to reduce radioactivity by half, is about 5,730 years, it makes it possible to date a sample up to about 60,000 years old, although carbon dating is often supplemented with other dating methods to extend accuracy and able to test samples even older than 60,000 years.

Unfortunately, according to a study done in 2015, climate changed caused by human activity is breaking carbon dating in the future. The carbon dioxide that comes from the fossil fuels that humans are burning could skew the carbon age of any new organic material created today. Fossil fuels come from old organic material that has already depleted its carbon 14, so new organic material appears older than it is. Even though new carbon-14 is created by cosmic rays bombarding the atmosphere, it is unable to keep up with the pace of human emissions.

Further reading: Impact of fossil fuel emissions on atmospheric

radiocarbon and various applications of radiocarbon

over this century

# data[].attributes.body
We are often told that the Big Bang is the cause of the universe. But what is the evidence?

The answers comes lies within cosmic microwave background radiation, CMB for short. Cosmic microwave background radiation is thought to be leftover radiation from the Big Bang, the time in which the universe began. As the theory goes, when the universe was born, it underwent a rapid inflation and expansion.

You can't see this radiation with your naked eye, but it is everywhere in the universe, even right around you. It is invisible to humans because it is so cold, just over 2.725 Kelvin. This means that this radiation is most visible in the microwave part of the electromagnetic spectrum.

The radiation from the cosmic background radiation in was scattered off the electrons. Thus, photons wandered through the early universe, just as optical light wanders through a dense fog. The universe began 13.8 billion years ago, and the cosmic background radiation dates back to about 400,000 years after the Big Bang. That's because in the early stages of the universe, when it was just 1/100,000,000 its size today, its temperature was 237 million Kelvin, an extreme amount. This meant that atoms present at that time were quickly broken apart into its elementary particles, which are its protons, neutrons, and electrons, turning it into plasma.

Further reading: Cosmic background radiation on Phys.org

# data[].attributes.body
The fact that gamma rays can kill any living organism is oddly advantageous to the medical field, most notably during cancer treatments. Gamma rays kill living organisms in a process called irradiation, the process by which an object is exposed to nuclear radiation, which is normally very harmful in nature but incredibly effective when controlled.

High doses of gamma rays can kill cancerous cells in a process called radiation therapy. Lower doses, however, could lead to healthy cells becoming cancerous. The process of radiation therapy kills the DNA of cancerous cells, preventing growth or division with the use of a machine called an accelerator or radioactive sources placed inside the patient. The oncologist's main focus is to target the dose of radiation to the cancer cells as precisely as possible to avoid hurting healthy tissue, which would otherwise cause a whole range of side effects. Harming healthy cells is inevitable, though. Such side effects depend on the area of treatment. They include, when situated at:

The head and neck areas:

Dry mouth

Mouth and gum sores

Difficulty swallowing

Jaw stiffness

Lymphedema

Tooth decay

The horax:

Shortness of breath

Breast or nipple soreness

Shoulder stiffness

Cough

Fever

"Radiation pneumonia"

The stomach and abdomen:

Nausea

Vomiting

Diarrhea

The pelvis

Diarrhea

Rerectal bleeding

Bladder irritation

Infertility issues for both males and females

These side effects may sound scary, however, the benefits of radiation therapy often outweigh the side effects when does correctly.

Not to mention, gamma rays are also quite effective in sterilizing medical equipment, since they can easily pass through the packaging of medical equipment and kill living tissue such as viruses and bacteria. Obviously, they are not effective for cleaning off debris, though.

# data[].attributes.body
Smoke detectors are relatively common nowaday, but have you every wondered how they can pick up specifically pick up smoke and ignore all the other gasses it comes across?

The answer is that smoke detectors use a small amount of americium-241, a radioactive isotope of the americium element, to detect smoke. Ionization smoke detectors use americium as a source of alpha particles. Alpha particles from the americium source ionize air molecules. This makes some particles positively charged and some negatively charged. Two charged plates inside of the ionization smoke detector create a flow of positively and negatively charged ions. The smoke alarm triggers when smoke breaks the constant flow of ions.

Since alpha particles have a comparatively larger mass, they cannot travel very far. In fact, they can be shielded by a layer as thin as a layer of dead skin cells. Ionization smoke detectors have a small americium source secured and encased in a layer of foil and ceramic, which stops the alpha particles from traveling outside of the smoke detector. Because of this shielding, the smoke detector poses no radiation health risk when they are properly handled.

Smoke detectors are relatively safe. There is little to no health threat from ionization smoke detectors as long as the detector is not damaged and used as directed. Don't even try to remove the americium...

# data[].attributes.body
Radioactive waste is also one aspect of radiation that is often misunderstood. Many members of the general public often protest nearby nuclear power plants, concerned of the generation nuclear waste.

However, like all industries, the generation of electricity produces waste. Whatever fuel is used, the waste produced in generating electricity must be managed in ways that safeguard human health and minimize the impact on the environment.

“For radioactive waste, this means isolating or diluting it such that the rate or concentration of any radio-nuclides returned to the biosphere is harmless. To achieve this, practically all radioactive waste is contained and managed, with some clearly needing deep and permanent burial. From nuclear power generation, unlike all other forms of thermal electricity generation, all waste is regulated – none is allowed to cause pollution," according to the World Nuclear Association.

Nuclear power is characterized by the very large amount of energy produced from a very small amount of fuel, and the amount of waste produced during this process is also relatively small. However, much of the waste produced is radioactive and therefore must be carefully managed as hazardous material. All parts of the nuclear fuel cycle produce some radioactive waste and the cost of managing and disposing of this is part of the electricity cost (i.e. it is internalized and paid for by the electricity consumers).

All toxic waste needs be dealt with safely – not just radioactive waste – and in countries with nuclear power, radioactive waste comprises a very small proportion of total industrial hazardous waste generated.

Radioactive waste is not unique to the nuclear fuel cycle. Radioactive materials are used extensively in medicine, agriculture, research, manufacturing, non-destructive testing, and minerals exploration. Unlike other hazardous industrial materials the level of hazard of all radioactive waste – its radioactivity – diminishes with time.”

# data[].attributes.body
- MEFANET, Czech and Slovak medical faculties network. “Gamma Rays and Medicine.” WikiLectures, www.wikilectures.eu/w/Gamma_Rays_and_Medicine.
- “What Is Carbon-14 (14C) Dating? Carbon Dating Definition.” Carbon Dating Service, AMS Miami - Beta Analytic, 11 May 2021, www.radiocarbon.com/about-carbon-dating.htm.
- Howell, Elizabeth. “Cosmic Microwave Background: Remnant of the Big Bang.” Space.com, Space, 24 Aug. 2018, www.space.com/33892-cosmic-microwave-background.html.
- “Americium in Ionization Smoke Detectors.” EPA, Environmental Protection Agency, 27 Aug. 2019, www.epa.gov/radtown/americium-ionization-smoke-detectors.
- “How Radiation Can Be Detected - Nuclear Radiation - National 5 Physics Revision - BBC Bitesize.” BBC News, BBC, www.bbc.co.uk/bitesize/guides/zt9s2nb/revision/5.
- Types of Radioactivity: Alpha, Beta, and Gamma Decay. 2 July 2019, https://chem.libretexts.org/@go/page/161974.
- “Radioactive Waste Management.” Radioactive Waste Management | Nuclear Waste Disposal - World Nuclear Association, Apr. 2021, https://world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-wastes/radioactive-waste-management.aspx.
- Mackenzie, Macaela. “All the Scary Ways Your Phone's Blue Light Could Be Messing With Your Eyes.” Allure, Allure, 3 July 2018, www.allure.com/story/how-blue-light-affects-eyes.