Hypernyms (tenant is a kind of...): bearer; holder (the person who is in possession of a check or note or bond or document of title that is endorsed to him or to whoever holds it) Hyponyms (each of the following is a kind of tenant): cotenant (one of two or more tenants holding title to the same property)
Exposure from terrestrial radiation. The composition of the earth's crust is a major source of natural radiation. The main contributors are natural deposits of uranium, potassium and thorium which, in the process of natural decay, will release small amounts of ionizing radiation.-rays: X-rays are a form of radiation similar to gamma radiation but they are produced mainly by artificial means rather than from radioactive substances. Neutron radiation: Neutron radiation occurs when neutrons are ejected from the nucleus by nuclear fission and other processes.
Figure 1 depicts the typical distribution of exposure from all sources of back-ground radiation. As can be seen, natural background radia-tion is the largest source of radiation exposure to humans (50 percent). However, medical sources of radiation exposure are almost as large (48 percent).The remaining 2 percent comes from consumer products, occupational exposure, and industrial expo-sure, which includes the exposure from nuclear power plants. Each of these sources is discussed below.he in-crease in the medical use of radiation accounts for the largest part of the overall increase in radiation exposure over the last several years. However, like natural back-ground radiation, this dose is not evenly distributed across the population.