Radioactive radiations

When the earthquake is coming the radioactive radiation background is increasing and this is a typical sample of radiation forerunner. 

Methods Based on Measurement of Radioactive Radiation or Amount of Radioactive Isotope or Daughter Isotope in Materials ... 

Pohl-Ruling, J. and P. Fischer, The Dose Effect Relationship of Chromosome Aberrations to Alpha and Gamma Irradiation in a Population Subjected to an Increased Burden of Natural Radioactivity, Radiation Research 80 61-81 (1979)... 

In 1899, the Curies first reported the coloration of glass and porcelain and the formation of ozone from oxygen by radioactive radiation. Giesel (1900) noted that the coloration of alkali halides under these radiations was similar to the effect of cathode rays he also observed the decomposition of water. R Curie and Debierne (1901) observed continuous evolution of hydrogen and oxygen... 

About 1910, M. Curie suggested that ions were responsible for the chemical effects of radioactive radiations. Soon thereafter, mainly due to the pioneering work of Lind on gases, the notation M/N was introduced for a quantitative measure of the radiation effect, where N is the number of ion pairs formed and M is the number of molecules transformed—either created or destroyed. This notation, referred to as the ion pair yield, was most conveniently employed in gases where N is a measurable quantity. However, for some time the same usage was extended to condensed systems assuming that ionization did not depend on the phase. This, however, is not necessarily correct. The notation G was introduced by Burton (1947) and others to denote the number of species produced or destroyed per 100 eV absorption of ionizing radiation. In this sense, it is defined... 

X-rays, often used in radiation chemistry, differ from y-rays only operationally namely, X-rays are produced in machines, whereas y-rays originate in nuclear transitions. In their interaction with matter, they behave similarly—that is, as a photon of appropriate energy. Other radiations used in radiation-chemical studies include protons, deuterons, various accelerated stripped nuclei, fission fragments, and radioactive radiations (a, /, or y). 

Flammability or explosivity Corrosivity Toxicity Carcinogenicity or teratogenicity Breathability (noxious or poisonous fumes) Electrical (high voltage or current) Light (intense sources, such as lasers, UV lamps) Radioactivity/Radiation... 

Perhaps best known of Perrin s work is his spirited defense of kinetic theory and physical atomism entitled Les atomes (1913), in which he made use of his own work on Brownian motion, in combination with studies of cathode rays and x-rays, ionization, radioactivity, radiation, and quantum theory.72 About the time of the 1911 Solvay physics conference, Perrin shifted from Brownian motion to work on thin films, fluorescence, and photochemistry, partly to test the early quantum theory and especially to study individual atom-based fluctuations. 

The essential basis of this analysis is that element to be determined is made radioactive usually by slow neutrons irradiation and then this radioactivity (radiation emitted, on, y) is a measure of the mass of the element originally present. 

Lind [2] has defined radiation chemistry as the science of the chemical effects brought about by the absorption of ionizing radiation in matter. It should be distinguished from radiation damage which refers to structural transformation induced by irradiation, particularly in the solid state. The distinction is not always maintained, perhaps unconsciously, and sometimes both effects may be present simultaneously. Following a suggestion of M. Curie around 1910, that ions were responsible for the chemical effects of radioactive radiations, the symbol MjN was introduced to quantify the radiation chemical effect, where M is the number of molecules transformed (created or destroyed) and N is the number of ion pairs formed. Later, Burton [3] and others advocated the notation G for the number of species produced or destroyed per 100 eV (= 1.602 x 10 J) absorption of ionizing radiation. It was purposely defined as a purely experimental quantity independent of implied mechanism or assumed theory. 

A more satisfactory procedure involves a radioactive probe held a little above the water surface. The radioactive radiations ionise the air between the probe and the surface and ensure that they are at the same potential. The probe is connected to an electrometer having a very high input impedance which reads the surface potential. This procedure was pioneered by Guyot (70J and Frumkin [71J in the 1920s but has become much more convenient to use with the introduction of artificial radioactive isotopes and modern electronics. Americium 241 is particularly useful as the low energies of the a and y radiations produced only ionise the air in the immediate vicinity of the probe. 

Radioactive radiation affects living cells and can cause them to suffer cancer. Also, some inherent illnesses can be caused, and passed from one generation to another. 

The distribution of radioactivity in the plant was determined using X-ray films (macroautoradiographs). The radioactive radiation causes blackenings on the film. During the early development up to shoot elongation, a maximum of 7.5% of the radioactivity applied was taken up and translocated into the wheat stalks and leaves with the... 

The original name for these techniques was nuclear magnetic resonance (NMR), but the word nuclear has been dropped in medicine to avoid any association with radioactive radiation. This technique gives information about the environment in which the nuclei of atoms find themselves in molecules of compounds. It can be used to give information about individual molecules as well as producing images of soft biological tissues. 

Means of excitation - Light, Ultraviolet or Radioactive Radiation, etc. 

Radioimmunoassay (RIA) These assays rely on the use of radiolabels. Typically, antigen is labelled using a radioactive isotope, for example iodine-125 ( 1), and radioactivity (radiation emitted from tube) is measured using an appropriate counter (in this case a y radiation counter). This major technique and some applications are covered in more detail later. 

Zevos, N. Radioactivity, Radiation, and the Chemistry of Nuclear Waste, J. Chem. Educ. 2002, 79, 692-696. 

Radioactivity was discovered in 1896 in Paris by Henri Becquerel, who investigated the radiation emitted by uranium minerals. He found that photographic plates were blackened in the absence of light, if they were in contact with the minerals. Two years later (1898) similar properties were discovered for thorium by Marie Curie in France and by G. C. Schmidt in Germany. That radioactivity had not been discovered earher is due to fact that human beings, like animals, do not have sense organs for radioactive radiation. Marie Curie found differences in the radioactivity of uranium and uranium minerals and concluded that the minerals must contain still other radioactive elements. Together with her husband, Pierre Curie, she discovered polonium in 1898, and radium later in the same year. 

Absorption or scattering of radioactive radiation is applied in industry for measurement of thickness or for material testing. For example, the production of paper, plastic or metal foils or sheets can be controlled continuously by passing these materials between an encapsulated radionuclide as the radiation source and a detector combined with a ratemeter, as shown in Fig. 20.2. After appropriate calibration, the ratemeter directly indicates the thickness. The radionuclide is chosen in such a way that the radiation emitted is eflFectively absorbed in the materials to be checked. Thus, the thickness of plastic foils is measured by use of f emitters, whereas Cs or other y emitters are used for measuring the thickness of metal sheets. 

Another example of the application of encapsulated sources of radioactive radiation in technical installations is the control of material transport on conveyor belts. The counting rate of the ratemeter is a measure of the thickness or the density, respectively, of the material transported by the belt. By multiplication by the velocity of the conveyor belt, the mass of the transported material is obtained. In the same way, solids transported with gas streams can be determined. 

To obtain spectroscopic information, the radiant power transmitted, fluoresced, or emitted must be detected in some manner and converted into a measurable quantity. A detector is a device that indicates the existence of some physical phenomenon. Familiar examples of detectors include photographic film (for indicating the presence of electromagnetic or radioactive radiation), the pointer of a balance (for indicating mass differences), and the mercury level in a thermometer (for indicating temperature). The human eye is also a detector it converts visible radiation into an electrical signal that is passed to the brain via a chain of neurons in the optic nerve and produces vision. 

We have hitherto been occupied only with radiations produced artificially. As we know, there are also natural radiations, whicli are emitted by raddoactive substances, the process involving s )ontan(H)us change of the atoms of these substances into other atoms (Becquerel, 1896 P. and M. Curie, 1898 Rutherford, Soddy, 1902). We distinguish three different kinds of radioactive radiations ... 

Surovtsev, I., Borisov, Yu., Perekalsky, D., Figovsky, O., and Beilin, D. Attenuation of y-Radiation by Polymer Concrete and Its Resistance to Radioactive Radiation, ICPIC 2007, 12th International Congress on Polymers in Concrete, Chuncheon, Korea. 

Instrumentation and measurcmt l af radioactivity Radiation detectors. Some important biwironic circuit . The statistics of radioactive measurements. 

The danger from radioactive substances is mainly due to the detrimental effects of the emitted ionizing radiation however, there are also toxic effects at the level of biochemical reactions. The most iihportant effects of radioactive radiation from accumulated radionuclides are manifested at a much later date in the form of genetic consequences. There are also local effects, since the radionucfides are frequently accumulated in a certain critical organ ( °Sr in bones, Cs in muscles, etc.). Thus, the local radiation dose can exceed by a factor as high as 50 the mean whole-body dose. In many cases, tumour growth may be induced. 

---