Radioactivity is produced when a substance is exposed to radiation. There are many sources of radiation in the world, including the sun, atomic nuclei, and natural sources. Understanding radiation is an important part of understanding the nature of matter, as it helps us understand our surroundings. Here’s a quick primer on the subject.
Radiation
Radiation and radioactivity are both serious and common concerns, but not all radiation exposure is harmful. The exposure to radiation can be minimized by controlling the duration and distance from the source of radiation. Generally, the intensity of radiation declines with increasing distance from the source. In some cases, concrete and lead barriers can offer good protection from high levels of penetrating radiation. Nonetheless, certain types of contamination can remain in the body permanently.
The International Commission on Radiation Protection (ICRP) was formed in 1928 and is an important source of guidelines and advice on radiation protection. The commission is independent of governments and is not responsible to the UN. It has retained the LNT hypothesis as its guiding principle. The ICRP is an independent body that makes recommendations for the safety of people exposed to low levels of radiation.
In the field of science, radiation is measured in sieverts (Sv). This unit of measurement takes into account the biological effects of radiation. A single sievert corresponds to one gray of beta radiation, 20 sieverts to alpha particles, and ten to twelve sieverts to neutrons. The amount of radiation in one sievert depends on the source of radiation. Hence, it is very important to understand the different ways radiation is measured and the differences between them.
Radiation is a natural phenomenon. It is common throughout the universe. Humans are naturally exposed to small amounts of radiation. Besides, some of us are sensitive to the effects of radiation on our bodies. Radiation, if not eliminated, can cause cancer and other genetic damage.
Atomic nuclei
Atomic nuclei give off different kinds of radiation. These radiations are emitted when the atoms’ nuclei undergo spontaneous transformation. In most cases, the nucleus releases alpha and beta particles, and in some cases, gamma rays. The amount of radioactivity produced depends on the percentage of unstable nuclei and the frequency of nuclear decay.
Atomic nuclei are dense groups of protons and neutrons. Protons and neutrons make up an atom, and they are connected to one another by a weak nuclear force. Protons are electrically neutral, but they also contribute mass to the atom. Neutrons and protons share a mass of about 86.6 g, which is why they give off a lot of energy.
Radioactivity has a variety of uses. It is used in medicine, chemistry, and materials science, and it is vital to our national security. For example, the DOE Isotope program supports research that produces actinium-225, which is used in medical equipment. It is also used in research on cancer treatments. While radioactivity has been around for centuries, only in the nineteenth century was it studied in great detail.
A model that accounted for the properties of a neutron was proposed by J.J. Thomson. The composite neutron model accounted for the neutron’s great penetrating power and its electrical neutrality. This was a legacy of the 1920s view that only two elementary particles existed – the proton and the electron. Nevertheless, it was the first to show that these two elements could be separated from each other.
The nuclear force is a strong attraction that binds nuclei together. This force is weaker than the electromagnetic force repulsion. The residual strong force decays quickly and is limited in range. Therefore, only small nuclei can be completely stable. Lead-208 is a good example. It contains 208 nucleons, 126 neutrons, and 82 protons. Larger nuclei, on the other hand, tend to be unstable and short-lived.
Radiation from the sun
Radiation is energy that moves through space, such as rays from the sun. It can be in the form of high-speed particles with an electric and magnetic field. All matter is made up of atoms, with the nucleus carrying a positive electrical charge and electrons carrying a negative charge. When an atom undergoes a reaction with radiation, the atom changes state and releases energy.
The Sun is the biggest source of radiation on Earth. Its radiation includes all wavelengths of the electromagnetic spectrum, and most of it is in the visible, infrared, and ultraviolet ranges. It also emits solar flares, which are massive explosions on the surface of the Sun. These flares release enormous amounts of energy into space and can cause serious damage to astronauts and equipment.
Radiation from the sun is a natural source of radioactivity, and a particle from the sun could have an unintended effect. Researchers at Purdue found that the decay rate of neutrinos emitted from the sun varies as the Earth orbits the sun. Ultimately, these results could lead to an accurate prediction of solar flares.
In 1895, Henri Becquerel noticed that a uranium compound, potassium uranyl sulfate, had higher activity than pure uranium. This observation led to the discovery of uranium and other radioactive elements.
Radiation from the sun produces alpha and beta particles. Alpha particles, for example, are not very far away and can be stopped by a sheet of paper. Gamma particles, on the other hand, do not travel very far.
Natural radioactivity
Natural radioactivity is an important phenomenon in our environment. It comes from two major sources: cosmic radiation and the decay of naturally occurring radionuclides. The primordial radionuclides, such as uranium, exist in trace amounts in the Earth’s crust, and the decay products of those elements are found in the atmosphere. They have half-lives that are comparable to the earth’s age.
The composition of natural radioactivity in rocks varies considerably depending on the minerals in them. In the crust, uranium, thorium, and potassium are concentrated in different proportions. This is because the composition of each rock type, its genesis, and its environment influences the proportions of these elements. A comparison of the concentrations in different sedimentary rocks reveals that each rock type is unique. In some cases, the ratios are quite different from those found in intrusive rocks.
In the United States, there have been extensive studies on natural gamma-radiation background. Exposure rates have been measured to range from less than 1 uR/h to up to 20 uR/h in some areas. In Chester, New Jersey, the Environmental Measurements Laboratory has a rural background monitoring station. This site measures the levels of radon and decay products.
The exposure level to radon is two-fold higher than that from other sources. Humans are exposed to approximately 2 mSv of radon each year. Consequently, the dose received by humans from other sources of natural radiation is approximately four-fold higher than the amount of radon in a typical residence. Hence, there is a significant variation in the amount of radon in different communities, and it is important to understand the ramifications of existing exposure levels.
Radionuclides in nature vary in chemical and physical properties. For example, in uranium, natural radionuclides range from inert gas to a readily absorbed cation. These properties determine how radionuclides behave in surface disposal environments and in fuel processing. They also contribute to the background radiation dose.
Induced radioactivity
Induced radioactivity is a type of radioactivity that is caused by neutron radiation. It is less common than most other types of radiation and occurs when neutrons interact with the nucleus of an atom. During the process of radioactivity, neutrons break through the electron cloud surrounding the atom and absorb into the nucleus. They then change the nuclear configuration and make it unstable.
Induced radioactivity is also called artificial radioactivity or man-made radioactivity. It is a method of making previously stable materials radioactive. One example is bombarding aluminium with alpha particles. When this happens, aluminium releases radio phosphorus. The process is not limited to atomic weapons; it can also be applied to other materials.
When irradiating a product, the activity should be measured as soon as possible after the process is completed. The count should be repeated if it exceeds the LC limit. In case of higher activity, the product should be evaluated for potential hazard and should be tested for radioactivity. The amount of induced radioactivity that is released should be proportional to the LC limit and the half-life.
Various elements can undergo induced radioactivity through neutron reactions. The amount of radioactive nuclides produced depends on the particle type. This is done through different processes. The first phase involves the use of germanium detectors to determine the amount of radioactive particles in a material. This method requires the use of an expensive spectrometer and complex setup. After this, a certificate from an approved laboratory is issued.
Induced radioactivity is usually caused by neutron activation, a process in which an atomic nucleus captures a neutron. This process generates a heavier isotope of the same chemical substance. Depending on the chemical element, the heavier isotopes may be stable or unstable.
