View Full Term. By clicking sign up, you agree to receive emails from Safeopedia and agree to our Terms of Use and Privacy Policy. Radioactive decay is used to describe what happens to the nucleus of an unstable atom when it loses energy and emits radiation.
Any material that emits any of the different forms of radiation is deemed radioactive. The term radioactive decay is more commonly known as radioactivity, is also called nuclear decay and involves any material that is considered radioactive.
An unstable atom is an atom that does not have enough binding energy to keep the nucleus of the atom together due to an imbalance of protons and neutrons.
This is due to an excess of either protons or neutrons. There are several different kinds of radiation that are emitted from an unstable atom, which include alpha particles, beta particles, gamma rays and conversion electrons. Subscribe to the Safeopedia newsletter to stay on top of current industry trends and up-to-date know-how from subject matter authorities. 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 unbalanced atoms called radionuclides. Elements in the periodic table can take on several forms. Some of these forms are stable; other forms are unstable. Typically, the most stable form of an element is the most common in nature. However, all elements have an unstable form. Unstable forms emit ionizing radiation and are radioactive.
There are some elements with no stable form that are always radioactive, such as uranium. Elements that emit ionizing radiation are called radionuclides. Glances at Europe Horace Greeley.
Elements of Agricultural Chemistry Thomas Anderson. One or more different nuclei are formed and usually particles and gamma rays are emitted Sometimes shortened to: decay Also called: disintegration.
The spontaneous transformation of an unstable atomic nucleus into a lighter one, in which radiation is released in the form of alpha particles, beta particles, gamma rays, and other particles. The rate of decay of radioactive substances such as carbon 14 or uranium is measured in terms of their half-life.
See also decay radioisotope. All rights reserved. To measure the Track Profile Technique TPT of alpha particle as Figure 5 you must irradiate the sides the edges of the detector by Am source of alpha particle with energy of five under normal incidence.
The track profile of deferent energy of alpha particle at deferent bulk etch rate. The method involves a direct measurement of the track lengths in both phases of evolution; the acute-conical and the over etched phases.
Accordingly, the maximum value of the track length L max at the saturation point and also the corresponding saturation time t sat , which is the time required for track length to reach the maximum and constant value, to be determined in accordance with the energy of the alpha particle which in turn can be used to calculate V B according to the relation [ 6 ]. Track profile was obtained as mentioned before and the range of certain particle track energy in the detector was measured using the relation.
Table 1 show that the L max depends on the energy of the incident particle while the t R not depends only on the energy of the incident particle but also on the etching rates, particularly the bulk etch rate V B which in turn controlled by the etching conditions; the concentration, and the temperature of the etching solution. The bulk etch rate V B was varying from 1. All values of V B were dependent on the etching conditions. The value of L max for the same energy is constant in the same matter.
The range of the particle energy dependent on the density of medium. The concentration of the solution and temperature are used to elucidate the path of the particles and have no effect along the path. The value of L max does not affect by increase in the concentration or in the temperature of the etching solution, while the time needed to reach to the end of track t R is change with change the condition of etching. The values of L max were The result show that, the range of alpha energies 4, 5 and 5.
This value corresponds to the theoretical values shown in Table 1. The maximum track length, range, the saturation time and bulk etch rate with different energy of alpha particle in CR39 detector. The equilibrium concentration of radon C eq determined from the track density by using the following relation. Where M is the mass of sample kg.
Thermal neutron activation analysis is used as the primary method for determining the element in any sample. This analysis is carried out inside the reactor with a flow of 3. Long-lived radio nuclides are determined using activation with thermal neutrons. First, the samples are filled in aluminum cups.
With a 2-hour irradiation time, then re-encapsulate after irradiation and then measured after 4 days of cooling and a second time after 20 days of cooling, using a high-purity Germanium Mono-Germanium Spectrometer HPGe ray with a precision of 2.
Then gamma spectra are analyzed and then the concentrations of different detected elements are estimated [ 10 ]. This method give the different element in air or in soil for example in Jazan region we can measure the different heavy element in air by using this technique.
Figures 6 and 7 were shown that the concentrations of heavy elements in Airport and Cady mall in PM The elements in TSP sample show in Figures 8 and 9. PM10—Airport zone: concentrations of heavy elements.
PM10—Cady mall zone: concentrations of heavy elements. TSP—Mountain neighborhood zone: concentrations of heavy elements. TSP—an industrial zone: concentrations of heavy elements. By adopting the level of concentration of elements in the atmosphere as the ranking standard, barium, calcium, iron and zinc elements were found to be the most dominant elements in the Jazan region of Saudi Arabia.
It was observed that the concentration depends on the study areas, as the industrial regions had the highest concentration of barium, iron, and zinc, whereas the market areas had the lowest concentration, especially barium and calcium.
Barium concluded that the main source of barium traces is car paints. It was also found that the concentration of zinc traces in the airport area and in the industrial zone samples. The main sources of zinc impacts in Jizan are tire wear, brake wear and exhaust emissions.
Therefore, we can ensure that zinc emissions are due to industrial processes, especially those related with tire wear and wear. Tires and brake pads are made of vulcanized rubber in the presence of a stimulant.
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