Types of radiation emitted

The same type of radiation emitted by different isotopes may differ signifieantly in energy, e.g. y-radiation from potassium-42 has about four times the energy of y-radiation from gold-198. 

The most common types of radiation emitted by radioactive nuclei are a particles (the nuclei of helium atoms), /3 particles (fast electrons ejected from the nucleus), and 7 rays (high-frequency electromagnetic radiation). 

The range in tissues and linear energy transfer (LET) depend on the type of radiation emitted and its energy. The potent lethality of Auger and low-energy conversion electrons is demonstrated by intranuclear localization of the radioisotope due to their short ranges (about one cell nucleus in diameter). Alpha particles have ranges of several cell diameters (40-90 pm) and are effective in... 

On the other hand, for molecules, the electronic transitions result in bands lO SOnm in width due to the changes in vibrational energy levels which also occur. A third type of radiation emitted by stars in the near-UV visible near-IR region is a continuum emission originating from hot particles e.g. hot AI2O3 particles) but this is considered to be grey body radiation and does not contribute to the colour of the star. 

All methods of radiometric analysis involve, of course, the use. of various radiation detection devices, The devices available for measuring radioactivity will vary with the types of radiations emitted by the radioisotope and the kinds of radioactive material. Ionization chambers are used for gases Geiger-Miiller and proportional counters for solids liquid scintillation counters for liquids and solutions and solid crystal or semi-conductor detector scintillation counters for liquids and solids emitting high-energy radiations. Each device can be adopted to detect and measure radioactive material in another state, e.g., solids can be assayed in an ionization chamber. The radiations interact with the detector to produce a signal,... 

To outline the different types of radiation emitted from some isotopes. 

While reading about the discovery of radioactivity, several questions may have occurred to you. Which atomic nuclei are radioactive What types of radiation do radioactive nuclei emit It is best to start with the second question first, and explore the types of radiation emitted by radioactive sources. 

With proper safety procedures, radiation can be very useful in many scientific experiments. Neutron activation analysis is used to detect trace amounts of elements present in a sample. Computer chip manufacturers use this technique to analyze the composition of highly purified silicon wafers. In the process, the sample is bombarded with a beam of neutrons from a radioactive source, causing some of the atoms in the sample to become radioactive. The type of radiation emitted by the sample is used to determine the types and quantities of elements present. Neutron activation analysis is a very sensitive measurement technique capable of detecting quantities of less than 1 X 10 9 g. 

Describe the common types of radiation emitted when nuclei undergo radioactive decay Write and balance eqwtions that describe nuclear reactions... 

Nuclei whose neutron-to-proton ratios lie outside the stable region undergo spontaneous radioactive decay by emitting one or more particles or electromagnetic rays or both. The type of decay that occurs usually depends on whether the nucleus is above, below, or to the right of the band of stability (Figure 26-1). Common types of radiation emitted in decay processes are summarized in Table 26-3. 

Any radionuclide, whatever the type of radiation emitted, is characterized by its half-life T (Table 17.1), which is the time taken for half of corresponding atom population in the sample to decompose (from initial time, t = 0). Calling A the radioactive decay constant, the law of radioactivity decay allows calculation of the number of atoms N present after time t for a population containing Nq atoms initially. The integrated form of this law is written as equation 17.4 ... 

Safety considerations are based on the magnitude of the half-life, shielding, distance from the radioactive source, time of exposure, and type of radiation emitted. We are never entirely free of the effects of radioactivity. Background radiation is normal radiation attributable to our surroundings. 

The manufacturing and handling of radiopharmaceuticals is potentially hazardous. The types of radiation emitted and the half-lives of the radioactive isotopes are parameters contributing to the level of risk. Particular attention must be paid to the prevention of cross-contamination, to the retention of radionuclide contaminants, and to waste disposal. Special consideration may be necessary with reference to the small batch sizes made frequently for many radiopharmaceuticals. Due to their short half-life some radiopharmaceuticals are released before completion of certain Quality Control tests. In this case, the continuous assessment of the effectiveness of the Quality Assurance system becomes very important. 

Nuclear emissions and x-rays are called ionizing radiation. They may have energies in the millions of electron volts (MeV) compared to the 2 to 3 electron volts (eV) of visible light. Table 10-3 is a list of some radioactive isotopes used as radiation sources along with the types of radiation emitted and their energy. 

Nuclide Main type of radiation emitted Half-life... 

One ofthe first considerations is to select the radionuclide that is to be used in the research. The half-life, the type of radiation emitted, the energies of the emissions, and the chemical properties of the radioisotopes are factors to be evaluated. 

Depending on the type of radiation emitted, at least three different types of measuring instruments will be required in order to be able to carry out total activity measurements for all radionuclides or radionuclide groups ... 

The intensity of radiation depends on the number of disintegrations as well as on the energy and type of radiation emitted. One common unit for the absorbed dose of radiation is the rad (radiation absorbed dose), which is the amount of radiation that results in the absorption of 1 X 10 J per kilogram of irradiated material. The biological effect of radiation also depends on the part of the body irradiated and the type... 

Placing some shielding between themselves and the source—the relationship between shielding and protection depends on the type of radiation emitted by the source and the nature of the shielding material used. 

Some nuclei are unstable and undergo radioactive decay. The common types of radiation emitted during decay processes are alpha, beta, and gamma, which can be... 

Uranium-238 is the most abundant naturally occurring isotope of uranium. It undergoes radioactive decay to form other isotopes. In the first three steps of this decay, uranium-238 is converted to thorium-234, which is converted to protactinium-234, which is converted to uranium-234. Assume that only one particle in addition to the daughter is produced in each step, and use equations for the decay processes to determine the type of radiation emitted during each step. 

Samma radiation Very short wave electromagnetic radiation emitted as a result of radioactive decay. It is the least ionizing and most penetrating of the three types of radiation emitted in radioactive decay. It will penetrate a thick metal sheet and is only stopped by over 15 cm of lead or by thick layers of concrete. 

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