Ionizing radiation comes from x-ray machines, cosmic particles from outer space and radioactive elements. Radioactive elements emit ionizing radiation as their atoms undergo radioactive decay. Radioactive decay is the emission of energy in the form of ionizing radiation ionizing radiation Radiation with so much energy it can knock electrons out of atoms.
The ionizing radiation that is emitted can include alpha particles alpha particles A form of particulate ionizing radiation made up of two neutrons and two protons. Alpha particles pose no direct or external radiation threat; however, they can pose a serious health threat if ingested or inhaled. Some beta particles are capable of penetrating the skin and causing damage such as skin burns. Beta-emitters are most hazardous when they are inhaled or swallowed.
Gamma rays can pass completely through the human body; as they pass through, they can cause damage to tissue and DNA. Radioactive decay occurs in unstable atoms called radionuclides. The energy of the radiation shown on the spectrum below increases from left to right as the frequency rises. Other agencies regulate the non-ionizing radiation that is emitted by electrical devices such as radio transmitters or cell phones See: Radiation Resources Outside of EPA.
Alpha particles come from the decay of the heaviest radioactive elements, such as uranium , radium and polonium. Even though alpha particles are very energetic, they are so heavy that they use up their energy over short distances and are unable to travel very far from the atom. The health effect from exposure to alpha particles depends greatly on how a person is exposed.
Alpha particles lack the energy to penetrate even the outer layer of skin, so exposure to the outside of the body is not a major concern. Inside the body, however, they can be very harmful. If alpha-emitters are inhaled, swallowed, or get into the body through a cut, the alpha particles can damage sensitive living tissue.
The way these large, heavy particles cause damage makes them more dangerous than other types of radiation. The ionizations they cause are very close together - they can release all their energy in a few cells. This results in more severe damage to cells and DNA. These particles are emitted by certain unstable atoms such as hydrogen-3 tritium , carbon and strontium Beta particles are more penetrating than alpha particles, but are less damaging to living tissue and DNA because the ionizations they produce are more widely spaced.
Since it penetrates so easily, it is some of the most useful radiation for medical purposes. Some of the most widely used gamma emitters are cobalt, cesium, and technetiumm. Cesium is used widely in radiotherapy - the treatment of cancer using gamma rays - as well as being used to measure soil density at construction sites and to investigate the subterranean layers of the Earth in oil wells. Cobalt is used to sterilize medical equipment and irradiate food, killing bacteria and pasteurizing the food.
Technetiumm which has a shorter half-life than technetium is the most widely used for diagnostic medical tests to investigate the brain, bone, and internal organs. As well, exposure to gamma radiation can improve the durability of wood and plastics, and is thus used to toughen flooring in high-traffic areas. In addition, uranium and uranium - used in fuel for nuclear power plants - undergo both alpha and gamma decays when used.
Immediately following the fission process, gamma rays are released, resulting in high levels of radiation present around the reactor. However, safety precautions are in line to ensure that workers do not get close enough to this radioactive area to be harmed.
Fossil Fuels. Nuclear Fuels. Acid Rain. Climate Change. Climate Feedback. The rest is in the form of neutrinos , which are extremely weakly interacting particles with nearly zero mass. In the later stages of a star's lifetime, when it runs out of hydrogen fuel, it can form increasingly more massive elements through fusion, up to and including iron, but these reactions produce a decreasing amount of energy at each stage.
Another familiar source of gamma rays is nuclear fission. Lawrence Berkeley National Laboratory defines nuclear fission as the splitting of a heavy nucleus into two roughly equal parts, which are then nuclei of lighter elements. In this process, which involves collisions with other particles, heavy nuclei, such as uranium and plutonium, are broken into smaller elements, such as xenon and strontium. The resulting particles from these collisions can then impact other heavy nuclei, setting up a nuclear chain reaction.
Energy is released because the combined mass of the resulting particles is less than the mass of the original heavy nucleus. Other sources of gamma rays are alpha decay and gamma decay. Alpha decay occurs when a heavy nucleus gives off a helium-4 nucleus, reducing its atomic number by 2 and its atomic weight by 4. This process can leave the nucleus with excess energy, which is emitted in the form of a gamma ray.
Gamma decay occurs when there is too much energy in the nucleus of an atom, causing it to emit a gamma ray without changing its charge or mass composition. Gamma rays are sometimes used to treat cancerous tumors in the body by damaging the DNA of the tumor cells.
However, great care must be taken, because gamma-rays can also damage the DNA of surrounding healthy tissue cells. One way to maximize the dosage to cancer cells while minimizing the exposure to healthy tissues is to direct multiple gamma-ray beams from a linear accelerator, or linac, onto the target region from many different directions.
This is the operating principle of CyberKnife and Gamma Knife therapies.
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