Ionizing Radiation. Test Your Knowledge Which of the following statements are true about ionizing radiation?
The correct answer is d. The correct answer is e. The correct answer is a. Gamma rays are emitted from the nucleus while X-rays are emitted from outside the nucleus. Ionizing radiation can fall into two categories: natural and manmade. Ionizing radiation that comes from natural sources is typically at low levels.
This means that the usual amount of ionizing radiation from natural sources absorbed by our bodies dose is small. For more information on possible health effects from radiation and radiation dose, click here.
These low levels of exposure vary with location, altitude and type of building materials used in home construction. You may also be exposed to the radioactive gas radon if your house or building has a leaky foundation. Every day, we use Ionizing radiation to help us live healthy lives. Ionizing radiation is found in smoke detectors, used to disinfect medical instruments and blood, and to perform many other tasks in our daily lives. It is also a byproduct of nuclear power generation. Our main exposure to ionizing radiation in manmade sources is through the use of diagnostic medical exams.
Ionizing radiation can penetrate the human body and the radiation energy can be absorbed in tissue. This has the potential to cause harmful effects to people, especially at high levels of exposure.
Natural sources of ionizing radiation usually release ionizing radiation at low levels, which also means the amounts of radiation absorbed by our bodies doses is usually small. Natural sources of ionizing radiation include radioactive elements that are naturally in our body. For example, a very small fraction of the potassium in our bodies is radioactive. Radon, however, is a natural radioactive gas found in rock formations that can release higher levels of radiation that can pose health risks.
It is the second leading cause of lung cancer in the United States. The levels of radon in your home or building depend on a variety of factors. You can test your home or building to determine whether you or your family is at risk of high levels of radon exposure.
For more information on radon, click here. Medical diagnostic exams are the main manmade source of ionizing radiation exposure in the U. The goal of medical diagnostic imaging is for the benefits to far outweigh the risks. For example, a Po atom has 84 protons and neutrons, and is unstable i. To become more stable, the Po atom ejects an alpha particle, consisting of two protons and two neutrons. Having lost two protons and two neutrons, the radioactive Po atom becomes stable lead Pb , with 82 protons and neutrons.
Negatively-charged, fast-moving electrons emitted from the nucleus of various radionuclides. Unstable atoms with a high neutron-to-proton ratio emit negatively-charged beta particles. Positively-charged, fast-moving electrons emitted from the nucleus of certain radionuclides. Unstable atoms with a low neutron-to-proton ratio can emit positrons.
For example, a carbon atom has six protons and eight neutrons, and is unstable i. To become more stable, the C atom releases radiation by turning a neutron into a proton and ejecting an electron i. Having gained a proton and lost a neutron, the radioactive C atom becomes stable nitrogen N , with seven protons and 7 neutrons. Fluorine F is an example of a positron-emitting radionuclide that is commonly used in medical facilities for positron emission tomography PET scanning.
An F atom has nine protons and nine neutrons, and is unstable i. To become more stable, the F atom releases radiation by turning a proton into a neutron and ejecting a positron. Having gained a neutron and lost a proton, the radioactive F atom becomes stable oxygen O , with eight protons and 10 neutrons. Neutral i. Neutrons are high-speed nuclear particles that are the only type of ionizing radiation that can make objects radioactive. Nuclear fission and fusion reactions, as well as neutron sources e.
For example, neutrons would be produced from the detonation of a fissile nuclear weapon, such as an improvised nuclear device IND. High-energy electromagnetic photons emitted from the nucleus of an unstable, excited atom. Gamma rays are pure energy and can travel great distances at high speed. Gamma rays are often emitted along with alpha or beta particles during radioactive decay e. High-energy electromagnetic photons emitted from outside the nucleus. The primary difference between X-rays and gamma rays is that X-rays are emitted from processes outside the nucleus, but gamma rays originate inside the nucleus.
Radioactive decay is a process by which unstable i. The rate of radioactive decay for each radioactive element is described by its half-life, or the amount of time it takes for around half of the radioactive atoms present to decay to a more stable form. Half-lives for different radioactive elements vary from fractions of seconds to billions of years. Unstable radioactive atoms can go through a series of decays, or disintegrations, before reaching a stable form.
Th has a half-life of 24 days and decays by beta particle emission to protactiniumm Pam , which has a half-life of only 1. As shown in the aturally-occurring U decay series, the final product of the decay series is lead Pb , which is stable.
Of note in this series is radon Rn , a radioactive gas that poses an inhalation hazard to workers and the public see the Hazard Recognition page.
Source: U. Geological Survey. Uranium decay series naturally-occurring , which produces alpha, beta, and gamma radiation not shown. Radioactivity is the number of energized particles or photons emitted by a source of radioactive material per unit of time. Another way to describe radioactivity is the number of decays also described as disintegrations occurring per unit of time. Units of measurement for radioactivity are the Curie Ci, traditional U.
What Happens to the Radiation Emitted? Ionizing radiation particles e.
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